diff mbox series

[3/8] vhost scsi: alloc cmds per vq instead of session

Message ID 1600712588-9514-4-git-send-email-michael.christie@oracle.com
State Superseded
Headers show
Series vhost scsi: fixes and cleanups | expand

Commit Message

Mike Christie Sept. 21, 2020, 6:23 p.m. UTC 
We currently are limited to 256 cmds per session. This leads to problems
where if the user has increased virtqueue_size to more than 2 or
cmd_per_lun to more than 256 vhost_scsi_get_tag can fail and the guest
will get IO errors.

This patch moves the cmd allocation to per vq so we can easily match
whatever the user has specified for num_queues and
virtqueue_size/cmd_per_lun. It also makes it easier to control how much
memory we preallocate. For cases, where perf is not as important and
we can use the current defaults (1 vq and 128 cmds per vq) memory use
from preallocate cmds is cut in half. For cases, where we are willing
to use more memory for higher perf, cmd mem use will now increase as
the num queues and queue depth increases.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/vhost/scsi.c | 204 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 127 insertions(+), 77 deletions(-)

Comments

kernel test robot Sept. 22, 2020, 1:32 a.m. UTC | #1 
Hi Mike,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on vhost/linux-next]
[also build test WARNING on v5.9-rc6 next-20200921]
[cannot apply to target/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Mike-Christie/vhost-scsi-fixes-and-cleanups/20200922-031251
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: s390-randconfig-r022-20200920 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 4e8c028158b56d9c2142a62464e8e0686bde3584)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr));
                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:20:12: note: expanded from macro '___constant_swab32'
           (((__u32)(x) & (__u32)0x0000ff00UL) <<  8) |            \
                     ^
   In file included from drivers/vhost/scsi.c:45:
   In file included from include/uapi/linux/vhost.h:14:
   In file included from include/uapi/linux/vhost_types.h:16:
   In file included from include/linux/virtio_config.h:7:
   In file included from include/linux/virtio.h:7:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr));
                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:21:12: note: expanded from macro '___constant_swab32'
           (((__u32)(x) & (__u32)0x00ff0000UL) >>  8) |            \
                     ^
   In file included from drivers/vhost/scsi.c:45:
   In file included from include/uapi/linux/vhost.h:14:
   In file included from include/uapi/linux/vhost_types.h:16:
   In file included from include/linux/virtio_config.h:7:
   In file included from include/linux/virtio.h:7:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr));
                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:22:12: note: expanded from macro '___constant_swab32'
           (((__u32)(x) & (__u32)0xff000000UL) >> 24)))
                     ^
   In file included from drivers/vhost/scsi.c:45:
   In file included from include/uapi/linux/vhost.h:14:
   In file included from include/uapi/linux/vhost_types.h:16:
   In file included from include/linux/virtio_config.h:7:
   In file included from include/linux/virtio.h:7:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr));
                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:120:12: note: expanded from macro '__swab32'
           __fswab32(x))
                     ^
   In file included from drivers/vhost/scsi.c:45:
   In file included from include/uapi/linux/vhost.h:14:
   In file included from include/uapi/linux/vhost_types.h:16:
   In file included from include/linux/virtio_config.h:7:
   In file included from include/linux/virtio.h:7:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:511:46: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew(cpu_to_le16(value), PCI_IOBASE + addr);
                                            ~~~~~~~~~~ ^
   include/asm-generic/io.h:521:46: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel(cpu_to_le32(value), PCI_IOBASE + addr);
                                            ~~~~~~~~~~ ^
   include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
>> drivers/vhost/scsi.c:606:28: warning: variable 'cpu' is uninitialized when used here [-Wuninitialized]

           cmd->tvc_se_cmd.map_cpu = cpu;
                                     ^~~
   drivers/vhost/scsi.c:583:14: note: initialize the variable 'cpu' to silence this warning
           int tag, cpu;
                       ^
                        = 0
   21 warnings generated.

# https://github.com/0day-ci/linux/commit/aef0e1e9298ab68f2d7bdf1afb9a376641b993d5
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Mike-Christie/vhost-scsi-fixes-and-cleanups/20200922-031251
git checkout aef0e1e9298ab68f2d7bdf1afb9a376641b993d5
vim +/cpu +606 drivers/vhost/scsi.c

057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  571  
1a1ff8256af679 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  572  static struct vhost_scsi_cmd *
aef0e1e9298ab6 drivers/vhost/scsi.c      Mike Christie      2020-09-21  573  vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
95e7c4341b8e28 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  574  		   unsigned char *cdb, u64 scsi_tag, u16 lun, u8 task_attr,
95e7c4341b8e28 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  575  		   u32 exp_data_len, int data_direction)
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  576  {
aef0e1e9298ab6 drivers/vhost/scsi.c      Mike Christie      2020-09-21  577  	struct vhost_scsi_virtqueue *svq = container_of(vq,
aef0e1e9298ab6 drivers/vhost/scsi.c      Mike Christie      2020-09-21  578  					struct vhost_scsi_virtqueue, vq);
1a1ff8256af679 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  579  	struct vhost_scsi_cmd *cmd;
1a1ff8256af679 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  580  	struct vhost_scsi_nexus *tv_nexus;
b1935f687bb93b drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  581  	struct scatterlist *sg, *prot_sg;
3aee26b4ae9104 drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  582  	struct page **pages;
10e9cbb6b53111 drivers/vhost/scsi.c      Matthew Wilcox     2018-06-12  583  	int tag, cpu;
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  584  
9871831283e795 drivers/vhost/scsi.c      Asias He           2013-05-06  585  	tv_nexus = tpg->tpg_nexus;
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  586  	if (!tv_nexus) {
1a1ff8256af679 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  587  		pr_err("Unable to locate active struct vhost_scsi_nexus\n");
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  588  		return ERR_PTR(-EIO);
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  589  	}
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  590  
aef0e1e9298ab6 drivers/vhost/scsi.c      Mike Christie      2020-09-21  591  	tag = sbitmap_get(&svq->scsi_tags, 0, false);
4a47d3a1ff10e5 drivers/vhost/scsi.c      Nicholas Bellinger 2013-09-23  592  	if (tag < 0) {
1a1ff8256af679 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  593  		pr_err("Unable to obtain tag for vhost_scsi_cmd\n");
4a47d3a1ff10e5 drivers/vhost/scsi.c      Nicholas Bellinger 2013-09-23  594  		return ERR_PTR(-ENOMEM);
4a47d3a1ff10e5 drivers/vhost/scsi.c      Nicholas Bellinger 2013-09-23  595  	}
4a47d3a1ff10e5 drivers/vhost/scsi.c      Nicholas Bellinger 2013-09-23  596  
aef0e1e9298ab6 drivers/vhost/scsi.c      Mike Christie      2020-09-21  597  	cmd = &svq->scsi_cmds[tag];
3aee26b4ae9104 drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  598  	sg = cmd->tvc_sgl;
b1935f687bb93b drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  599  	prot_sg = cmd->tvc_prot_sgl;
3aee26b4ae9104 drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  600  	pages = cmd->tvc_upages;
473f0b15a4c97d drivers/vhost/scsi.c      Markus Elfring     2017-05-20  601  	memset(cmd, 0, sizeof(*cmd));
3aee26b4ae9104 drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  602  	cmd->tvc_sgl = sg;
b1935f687bb93b drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  603  	cmd->tvc_prot_sgl = prot_sg;
3aee26b4ae9104 drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  604  	cmd->tvc_upages = pages;
4824d3bfb9097a drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-07  605  	cmd->tvc_se_cmd.map_tag = tag;
10e9cbb6b53111 drivers/vhost/scsi.c      Matthew Wilcox     2018-06-12 @606  	cmd->tvc_se_cmd.map_cpu = cpu;
95e7c4341b8e28 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  607  	cmd->tvc_tag = scsi_tag;
95e7c4341b8e28 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  608  	cmd->tvc_lun = lun;
95e7c4341b8e28 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  609  	cmd->tvc_task_attr = task_attr;
3c63f66a0dcdd6 drivers/vhost/scsi.c      Asias He           2013-05-06  610  	cmd->tvc_exp_data_len = exp_data_len;
3c63f66a0dcdd6 drivers/vhost/scsi.c      Asias He           2013-05-06  611  	cmd->tvc_data_direction = data_direction;
3c63f66a0dcdd6 drivers/vhost/scsi.c      Asias He           2013-05-06  612  	cmd->tvc_nexus = tv_nexus;
1a1ff8256af679 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  613  	cmd->inflight = vhost_scsi_get_inflight(vq);
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  614  
1a1ff8256af679 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  615  	memcpy(cmd->tvc_cdb, cdb, VHOST_SCSI_MAX_CDB_SIZE);
95e7c4341b8e28 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  616  
3c63f66a0dcdd6 drivers/vhost/scsi.c      Asias He           2013-05-06  617  	return cmd;
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  618  }
057cbf49a1f082 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  619  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Dan Carpenter Sept. 23, 2020, 7:53 a.m. UTC | #2 
Hi Mike,

url:    https://github.com/0day-ci/linux/commits/Mike-Christie/vhost-scsi-fixes-and-cleanups/20200922-031251
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: i386-randconfig-m021-20200923 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/vhost/scsi.c:606 vhost_scsi_get_cmd() error: uninitialized symbol 'cpu'.

# https://github.com/0day-ci/linux/commit/aef0e1e9298ab68f2d7bdf1afb9a376641b993d5
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Mike-Christie/vhost-scsi-fixes-and-cleanups/20200922-031251
git checkout aef0e1e9298ab68f2d7bdf1afb9a376641b993d5
vim +/cpu +606 drivers/vhost/scsi.c

1a1ff8256af679c8 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  572  static struct vhost_scsi_cmd *
aef0e1e9298ab68f drivers/vhost/scsi.c      Mike Christie      2020-09-21  573  vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
95e7c4341b8e28da drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  574  		   unsigned char *cdb, u64 scsi_tag, u16 lun, u8 task_attr,
95e7c4341b8e28da drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  575  		   u32 exp_data_len, int data_direction)
057cbf49a1f08297 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  576  {
aef0e1e9298ab68f drivers/vhost/scsi.c      Mike Christie      2020-09-21  577  	struct vhost_scsi_virtqueue *svq = container_of(vq,
aef0e1e9298ab68f drivers/vhost/scsi.c      Mike Christie      2020-09-21  578  					struct vhost_scsi_virtqueue, vq);
1a1ff8256af679c8 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  579  	struct vhost_scsi_cmd *cmd;
1a1ff8256af679c8 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  580  	struct vhost_scsi_nexus *tv_nexus;
b1935f687bb93b20 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  581  	struct scatterlist *sg, *prot_sg;
3aee26b4ae91048c drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  582  	struct page **pages;
10e9cbb6b531117b drivers/vhost/scsi.c      Matthew Wilcox     2018-06-12  583  	int tag, cpu;
057cbf49a1f08297 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  584  
9871831283e79575 drivers/vhost/scsi.c      Asias He           2013-05-06  585  	tv_nexus = tpg->tpg_nexus;
057cbf49a1f08297 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  586  	if (!tv_nexus) {
1a1ff8256af679c8 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  587  		pr_err("Unable to locate active struct vhost_scsi_nexus\n");
057cbf49a1f08297 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  588  		return ERR_PTR(-EIO);
057cbf49a1f08297 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  589  	}
057cbf49a1f08297 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  590  
aef0e1e9298ab68f drivers/vhost/scsi.c      Mike Christie      2020-09-21  591  	tag = sbitmap_get(&svq->scsi_tags, 0, false);
4a47d3a1ff10e564 drivers/vhost/scsi.c      Nicholas Bellinger 2013-09-23  592  	if (tag < 0) {
1a1ff8256af679c8 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  593  		pr_err("Unable to obtain tag for vhost_scsi_cmd\n");
4a47d3a1ff10e564 drivers/vhost/scsi.c      Nicholas Bellinger 2013-09-23  594  		return ERR_PTR(-ENOMEM);
4a47d3a1ff10e564 drivers/vhost/scsi.c      Nicholas Bellinger 2013-09-23  595  	}
4a47d3a1ff10e564 drivers/vhost/scsi.c      Nicholas Bellinger 2013-09-23  596  
aef0e1e9298ab68f drivers/vhost/scsi.c      Mike Christie      2020-09-21  597  	cmd = &svq->scsi_cmds[tag];
3aee26b4ae91048c drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  598  	sg = cmd->tvc_sgl;
b1935f687bb93b20 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  599  	prot_sg = cmd->tvc_prot_sgl;
3aee26b4ae91048c drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  600  	pages = cmd->tvc_upages;
473f0b15a4c97d39 drivers/vhost/scsi.c      Markus Elfring     2017-05-20  601  	memset(cmd, 0, sizeof(*cmd));
3aee26b4ae91048c drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  602  	cmd->tvc_sgl = sg;
b1935f687bb93b20 drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  603  	cmd->tvc_prot_sgl = prot_sg;
3aee26b4ae91048c drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-21  604  	cmd->tvc_upages = pages;
4824d3bfb9097ac5 drivers/vhost/scsi.c      Nicholas Bellinger 2013-06-07  605  	cmd->tvc_se_cmd.map_tag = tag;
10e9cbb6b531117b drivers/vhost/scsi.c      Matthew Wilcox     2018-06-12 @606  	cmd->tvc_se_cmd.map_cpu = cpu;

"cpu" is never initialized.

95e7c4341b8e28da drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  607  	cmd->tvc_tag = scsi_tag;
95e7c4341b8e28da drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  608  	cmd->tvc_lun = lun;
95e7c4341b8e28da drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  609  	cmd->tvc_task_attr = task_attr;
3c63f66a0dcdd6cb drivers/vhost/scsi.c      Asias He           2013-05-06  610  	cmd->tvc_exp_data_len = exp_data_len;
3c63f66a0dcdd6cb drivers/vhost/scsi.c      Asias He           2013-05-06  611  	cmd->tvc_data_direction = data_direction;
3c63f66a0dcdd6cb drivers/vhost/scsi.c      Asias He           2013-05-06  612  	cmd->tvc_nexus = tv_nexus;
1a1ff8256af679c8 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  613  	cmd->inflight = vhost_scsi_get_inflight(vq);
057cbf49a1f08297 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  614  
1a1ff8256af679c8 drivers/vhost/scsi.c      Nicholas Bellinger 2015-01-31  615  	memcpy(cmd->tvc_cdb, cdb, VHOST_SCSI_MAX_CDB_SIZE);
95e7c4341b8e28da drivers/vhost/scsi.c      Nicholas Bellinger 2014-02-22  616  
3c63f66a0dcdd6cb drivers/vhost/scsi.c      Asias He           2013-05-06  617  	return cmd;
057cbf49a1f08297 drivers/vhost/tcm_vhost.c Nicholas Bellinger 2012-07-18  618  }

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Michael S. Tsirkin Sept. 24, 2020, 6:22 a.m. UTC | #3 
On Mon, Sep 21, 2020 at 01:23:03PM -0500, Mike Christie wrote:
> We currently are limited to 256 cmds per session. This leads to problems

> where if the user has increased virtqueue_size to more than 2 or

> cmd_per_lun to more than 256 vhost_scsi_get_tag can fail and the guest

> will get IO errors.

> 

> This patch moves the cmd allocation to per vq so we can easily match

> whatever the user has specified for num_queues and

> virtqueue_size/cmd_per_lun. It also makes it easier to control how much

> memory we preallocate. For cases, where perf is not as important and

> we can use the current defaults (1 vq and 128 cmds per vq) memory use

> from preallocate cmds is cut in half. For cases, where we are willing

> to use more memory for higher perf, cmd mem use will now increase as

> the num queues and queue depth increases.

> 

> Signed-off-by: Mike Christie <michael.christie@oracle.com>

> ---

>  drivers/vhost/scsi.c | 204 ++++++++++++++++++++++++++++++++-------------------

>  1 file changed, 127 insertions(+), 77 deletions(-)

> 

> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c

> index b22adf0..13311b8 100644

> --- a/drivers/vhost/scsi.c

> +++ b/drivers/vhost/scsi.c

> @@ -52,7 +52,6 @@

>  #define VHOST_SCSI_VERSION  "v0.1"

>  #define VHOST_SCSI_NAMELEN 256

>  #define VHOST_SCSI_MAX_CDB_SIZE 32

> -#define VHOST_SCSI_DEFAULT_TAGS 256

>  #define VHOST_SCSI_PREALLOC_SGLS 2048

>  #define VHOST_SCSI_PREALLOC_UPAGES 2048

>  #define VHOST_SCSI_PREALLOC_PROT_SGLS 2048

> @@ -189,6 +188,9 @@ struct vhost_scsi_virtqueue {

>  	 * Writers must also take dev mutex and flush under it.

>  	 */

>  	int inflight_idx;

> +	struct vhost_scsi_cmd *scsi_cmds;

> +	struct sbitmap scsi_tags;

> +	int max_cmds;

>  };

>  

>  struct vhost_scsi {

> @@ -324,7 +326,9 @@ static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)

>  {

>  	struct vhost_scsi_cmd *tv_cmd = container_of(se_cmd,

>  				struct vhost_scsi_cmd, tvc_se_cmd);

> -	struct se_session *se_sess = tv_cmd->tvc_nexus->tvn_se_sess;

> +	struct vhost_scsi_virtqueue *svq = container_of(tv_cmd->tvc_vq,

> +				struct vhost_scsi_virtqueue, vq);

> +	struct vhost_scsi_inflight *inflight = tv_cmd->inflight;

>  	int i;

>  

>  	if (tv_cmd->tvc_sgl_count) {

> @@ -336,8 +340,8 @@ static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)

>  			put_page(sg_page(&tv_cmd->tvc_prot_sgl[i]));

>  	}

>  

> -	vhost_scsi_put_inflight(tv_cmd->inflight);

> -	target_free_tag(se_sess, se_cmd);

> +	sbitmap_clear_bit(&svq->scsi_tags, se_cmd->map_tag);

> +	vhost_scsi_put_inflight(inflight);

>  }

>  

>  static u32 vhost_scsi_sess_get_index(struct se_session *se_sess)

> @@ -566,13 +570,14 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)

>  }

>  

>  static struct vhost_scsi_cmd *

> -vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,

> +vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,

>  		   unsigned char *cdb, u64 scsi_tag, u16 lun, u8 task_attr,

>  		   u32 exp_data_len, int data_direction)

>  {

> +	struct vhost_scsi_virtqueue *svq = container_of(vq,

> +					struct vhost_scsi_virtqueue, vq);

>  	struct vhost_scsi_cmd *cmd;

>  	struct vhost_scsi_nexus *tv_nexus;

> -	struct se_session *se_sess;

>  	struct scatterlist *sg, *prot_sg;

>  	struct page **pages;

>  	int tag, cpu;

> @@ -582,15 +587,14 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)

>  		pr_err("Unable to locate active struct vhost_scsi_nexus\n");

>  		return ERR_PTR(-EIO);

>  	}

> -	se_sess = tv_nexus->tvn_se_sess;

>  

> -	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);

> +	tag = sbitmap_get(&svq->scsi_tags, 0, false);

>  	if (tag < 0) {

>  		pr_err("Unable to obtain tag for vhost_scsi_cmd\n");

>  		return ERR_PTR(-ENOMEM);

>  	}



After this change, cpu is uninitialized.


>  

> -	cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[tag];

> +	cmd = &svq->scsi_cmds[tag];

>  	sg = cmd->tvc_sgl;

>  	prot_sg = cmd->tvc_prot_sgl;

>  	pages = cmd->tvc_upages;

> @@ -1065,11 +1069,11 @@ static void vhost_scsi_submission_work(struct work_struct *work)

>  				scsi_command_size(cdb), VHOST_SCSI_MAX_CDB_SIZE);

>  				goto err;

>  		}

> -		cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,

> +		cmd = vhost_scsi_get_cmd(vq, tpg, cdb, tag, lun, task_attr,

>  					 exp_data_len + prot_bytes,

>  					 data_direction);

>  		if (IS_ERR(cmd)) {

> -			vq_err(vq, "vhost_scsi_get_tag failed %ld\n",

> +			vq_err(vq, "vhost_scsi_get_cmd failed %ld\n",

>  			       PTR_ERR(cmd));

>  			goto err;

>  		}

> @@ -1373,6 +1377,83 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)

>  		wait_for_completion(&old_inflight[i]->comp);

>  }

>  

> +static void vhost_scsi_destroy_vq_cmds(struct vhost_virtqueue *vq)

> +{

> +	struct vhost_scsi_virtqueue *svq = container_of(vq,

> +					struct vhost_scsi_virtqueue, vq);

> +	struct vhost_scsi_cmd *tv_cmd;

> +	unsigned int i;

> +

> +	if (!svq->scsi_cmds)

> +		return;

> +

> +	for (i = 0; i < svq->max_cmds; i++) {

> +		tv_cmd = &svq->scsi_cmds[i];

> +

> +		kfree(tv_cmd->tvc_sgl);

> +		kfree(tv_cmd->tvc_prot_sgl);

> +		kfree(tv_cmd->tvc_upages);

> +	}

> +

> +	sbitmap_free(&svq->scsi_tags);

> +	kfree(svq->scsi_cmds);

> +	svq->scsi_cmds = NULL;

> +}

> +

> +static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds)

> +{

> +	struct vhost_scsi_virtqueue *svq = container_of(vq,

> +					struct vhost_scsi_virtqueue, vq);

> +	struct vhost_scsi_cmd *tv_cmd;

> +	unsigned int i;

> +

> +	if (svq->scsi_cmds)

> +		return 0;

> +

> +	if (sbitmap_init_node(&svq->scsi_tags, max_cmds, -1, GFP_KERNEL,

> +			      NUMA_NO_NODE))

> +		return -ENOMEM;

> +	svq->max_cmds = max_cmds;

> +

> +	svq->scsi_cmds = kcalloc(max_cmds, sizeof(*tv_cmd), GFP_KERNEL);

> +	if (!svq->scsi_cmds) {

> +		sbitmap_free(&svq->scsi_tags);

> +		return -ENOMEM;

> +	}

> +

> +	for (i = 0; i < max_cmds; i++) {

> +		tv_cmd = &svq->scsi_cmds[i];

> +

> +		tv_cmd->tvc_sgl = kcalloc(VHOST_SCSI_PREALLOC_SGLS,

> +					  sizeof(struct scatterlist),

> +					  GFP_KERNEL);

> +		if (!tv_cmd->tvc_sgl) {

> +			pr_err("Unable to allocate tv_cmd->tvc_sgl\n");

> +			goto out;

> +		}

> +

> +		tv_cmd->tvc_upages = kcalloc(VHOST_SCSI_PREALLOC_UPAGES,

> +					     sizeof(struct page *),

> +					     GFP_KERNEL);

> +		if (!tv_cmd->tvc_upages) {

> +			pr_err("Unable to allocate tv_cmd->tvc_upages\n");

> +			goto out;

> +		}

> +

> +		tv_cmd->tvc_prot_sgl = kcalloc(VHOST_SCSI_PREALLOC_PROT_SGLS,

> +					       sizeof(struct scatterlist),

> +					       GFP_KERNEL);

> +		if (!tv_cmd->tvc_prot_sgl) {

> +			pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");

> +			goto out;

> +		}

> +	}

> +	return 0;

> +out:

> +	vhost_scsi_destroy_vq_cmds(vq);

> +	return -ENOMEM;

> +}

> +

>  /*

>   * Called from vhost_scsi_ioctl() context to walk the list of available

>   * vhost_scsi_tpg with an active struct vhost_scsi_nexus

> @@ -1427,10 +1508,9 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)

>  

>  		if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) {

>  			if (vs->vs_tpg && vs->vs_tpg[tpg->tport_tpgt]) {

> -				kfree(vs_tpg);

>  				mutex_unlock(&tpg->tv_tpg_mutex);

>  				ret = -EEXIST;

> -				goto out;

> +				goto undepend;

>  			}

>  			/*

>  			 * In order to ensure individual vhost-scsi configfs

> @@ -1442,9 +1522,8 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)

>  			ret = target_depend_item(&se_tpg->tpg_group.cg_item);

>  			if (ret) {

>  				pr_warn("target_depend_item() failed: %d\n", ret);

> -				kfree(vs_tpg);

>  				mutex_unlock(&tpg->tv_tpg_mutex);

> -				goto out;

> +				goto undepend;

>  			}

>  			tpg->tv_tpg_vhost_count++;

>  			tpg->vhost_scsi = vs;

> @@ -1457,6 +1536,16 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)

>  	if (match) {

>  		memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn,

>  		       sizeof(vs->vs_vhost_wwpn));

> +

> +		for (i = VHOST_SCSI_VQ_IO; i < VHOST_SCSI_MAX_VQ; i++) {

> +			vq = &vs->vqs[i].vq;

> +			if (!vhost_vq_is_setup(vq))

> +				continue;

> +

> +			if (vhost_scsi_setup_vq_cmds(vq, vq->num))

> +				goto destroy_vq_cmds;

> +		}

> +

>  		for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) {

>  			vq = &vs->vqs[i].vq;

>  			mutex_lock(&vq->mutex);

> @@ -1476,7 +1565,22 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)

>  	vhost_scsi_flush(vs);

>  	kfree(vs->vs_tpg);

>  	vs->vs_tpg = vs_tpg;

> +	goto out;

>  

> +destroy_vq_cmds:

> +	for (i--; i >= VHOST_SCSI_VQ_IO; i--) {

> +		if (!vhost_vq_get_backend(&vs->vqs[i].vq))

> +			vhost_scsi_destroy_vq_cmds(&vs->vqs[i].vq);

> +	}

> +undepend:

> +	for (i = 0; i < VHOST_SCSI_MAX_TARGET; i++) {

> +		tpg = vs_tpg[i];

> +		if (tpg) {

> +			tpg->tv_tpg_vhost_count--;

> +			target_undepend_item(&tpg->se_tpg.tpg_group.cg_item);

> +		}

> +	}

> +	kfree(vs_tpg);

>  out:

>  	mutex_unlock(&vs->dev.mutex);

>  	mutex_unlock(&vhost_scsi_mutex);

> @@ -1549,6 +1653,12 @@ static void vhost_scsi_flush(struct vhost_scsi *vs)

>  			mutex_lock(&vq->mutex);

>  			vhost_vq_set_backend(vq, NULL);

>  			mutex_unlock(&vq->mutex);

> +			/*

> +			 * Make sure cmds are not running before tearing them

> +			 * down.

> +			 */

> +			vhost_scsi_flush(vs);

> +			vhost_scsi_destroy_vq_cmds(vq);

>  		}

>  	}

>  	/*

> @@ -1842,23 +1952,6 @@ static void vhost_scsi_port_unlink(struct se_portal_group *se_tpg,

>  	mutex_unlock(&vhost_scsi_mutex);

>  }

>  

> -static void vhost_scsi_free_cmd_map_res(struct se_session *se_sess)

> -{

> -	struct vhost_scsi_cmd *tv_cmd;

> -	unsigned int i;

> -

> -	if (!se_sess->sess_cmd_map)

> -		return;

> -

> -	for (i = 0; i < VHOST_SCSI_DEFAULT_TAGS; i++) {

> -		tv_cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[i];

> -

> -		kfree(tv_cmd->tvc_sgl);

> -		kfree(tv_cmd->tvc_prot_sgl);

> -		kfree(tv_cmd->tvc_upages);

> -	}

> -}

> -

>  static ssize_t vhost_scsi_tpg_attrib_fabric_prot_type_store(

>  		struct config_item *item, const char *page, size_t count)

>  {

> @@ -1898,45 +1991,6 @@ static ssize_t vhost_scsi_tpg_attrib_fabric_prot_type_show(

>  	NULL,

>  };

>  

> -static int vhost_scsi_nexus_cb(struct se_portal_group *se_tpg,

> -			       struct se_session *se_sess, void *p)

> -{

> -	struct vhost_scsi_cmd *tv_cmd;

> -	unsigned int i;

> -

> -	for (i = 0; i < VHOST_SCSI_DEFAULT_TAGS; i++) {

> -		tv_cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[i];

> -

> -		tv_cmd->tvc_sgl = kcalloc(VHOST_SCSI_PREALLOC_SGLS,

> -					  sizeof(struct scatterlist),

> -					  GFP_KERNEL);

> -		if (!tv_cmd->tvc_sgl) {

> -			pr_err("Unable to allocate tv_cmd->tvc_sgl\n");

> -			goto out;

> -		}

> -

> -		tv_cmd->tvc_upages = kcalloc(VHOST_SCSI_PREALLOC_UPAGES,

> -					     sizeof(struct page *),

> -					     GFP_KERNEL);

> -		if (!tv_cmd->tvc_upages) {

> -			pr_err("Unable to allocate tv_cmd->tvc_upages\n");

> -			goto out;

> -		}

> -

> -		tv_cmd->tvc_prot_sgl = kcalloc(VHOST_SCSI_PREALLOC_PROT_SGLS,

> -					       sizeof(struct scatterlist),

> -					       GFP_KERNEL);

> -		if (!tv_cmd->tvc_prot_sgl) {

> -			pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");

> -			goto out;

> -		}

> -	}

> -	return 0;

> -out:

> -	vhost_scsi_free_cmd_map_res(se_sess);

> -	return -ENOMEM;

> -}

> -

>  static int vhost_scsi_make_nexus(struct vhost_scsi_tpg *tpg,

>  				const char *name)

>  {

> @@ -1960,12 +2014,9 @@ static int vhost_scsi_make_nexus(struct vhost_scsi_tpg *tpg,

>  	 * struct se_node_acl for the vhost_scsi struct se_portal_group with

>  	 * the SCSI Initiator port name of the passed configfs group 'name'.

>  	 */

> -	tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,

> -					VHOST_SCSI_DEFAULT_TAGS,

> -					sizeof(struct vhost_scsi_cmd),

> +	tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg, 0, 0,

>  					TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS,

> -					(unsigned char *)name, tv_nexus,

> -					vhost_scsi_nexus_cb);

> +					(unsigned char *)name, tv_nexus, NULL);

>  	if (IS_ERR(tv_nexus->tvn_se_sess)) {

>  		mutex_unlock(&tpg->tv_tpg_mutex);

>  		kfree(tv_nexus);

> @@ -2015,7 +2066,6 @@ static int vhost_scsi_drop_nexus(struct vhost_scsi_tpg *tpg)

>  		" %s Initiator Port: %s\n", vhost_scsi_dump_proto_id(tpg->tport),

>  		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);

>  

> -	vhost_scsi_free_cmd_map_res(se_sess);

>  	/*

>  	 * Release the SCSI I_T Nexus to the emulated vhost Target Port

>  	 */

> -- 

> 1.8.3.1
diff mbox series

Patch

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index b22adf0..13311b8 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -52,7 +52,6 @@ 
 #define VHOST_SCSI_VERSION  "v0.1"
 #define VHOST_SCSI_NAMELEN 256
 #define VHOST_SCSI_MAX_CDB_SIZE 32
-#define VHOST_SCSI_DEFAULT_TAGS 256
 #define VHOST_SCSI_PREALLOC_SGLS 2048
 #define VHOST_SCSI_PREALLOC_UPAGES 2048
 #define VHOST_SCSI_PREALLOC_PROT_SGLS 2048
@@ -189,6 +188,9 @@  struct vhost_scsi_virtqueue {
 	 * Writers must also take dev mutex and flush under it.
 	 */
 	int inflight_idx;
+	struct vhost_scsi_cmd *scsi_cmds;
+	struct sbitmap scsi_tags;
+	int max_cmds;
 };
 
 struct vhost_scsi {
@@ -324,7 +326,9 @@  static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)
 {
 	struct vhost_scsi_cmd *tv_cmd = container_of(se_cmd,
 				struct vhost_scsi_cmd, tvc_se_cmd);
-	struct se_session *se_sess = tv_cmd->tvc_nexus->tvn_se_sess;
+	struct vhost_scsi_virtqueue *svq = container_of(tv_cmd->tvc_vq,
+				struct vhost_scsi_virtqueue, vq);
+	struct vhost_scsi_inflight *inflight = tv_cmd->inflight;
 	int i;
 
 	if (tv_cmd->tvc_sgl_count) {
@@ -336,8 +340,8 @@  static void vhost_scsi_release_cmd(struct se_cmd *se_cmd)
 			put_page(sg_page(&tv_cmd->tvc_prot_sgl[i]));
 	}
 
-	vhost_scsi_put_inflight(tv_cmd->inflight);
-	target_free_tag(se_sess, se_cmd);
+	sbitmap_clear_bit(&svq->scsi_tags, se_cmd->map_tag);
+	vhost_scsi_put_inflight(inflight);
 }
 
 static u32 vhost_scsi_sess_get_index(struct se_session *se_sess)
@@ -566,13 +570,14 @@  static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
 }
 
 static struct vhost_scsi_cmd *
-vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
+vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
 		   unsigned char *cdb, u64 scsi_tag, u16 lun, u8 task_attr,
 		   u32 exp_data_len, int data_direction)
 {
+	struct vhost_scsi_virtqueue *svq = container_of(vq,
+					struct vhost_scsi_virtqueue, vq);
 	struct vhost_scsi_cmd *cmd;
 	struct vhost_scsi_nexus *tv_nexus;
-	struct se_session *se_sess;
 	struct scatterlist *sg, *prot_sg;
 	struct page **pages;
 	int tag, cpu;
@@ -582,15 +587,14 @@  static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
 		pr_err("Unable to locate active struct vhost_scsi_nexus\n");
 		return ERR_PTR(-EIO);
 	}
-	se_sess = tv_nexus->tvn_se_sess;
 
-	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
+	tag = sbitmap_get(&svq->scsi_tags, 0, false);
 	if (tag < 0) {
 		pr_err("Unable to obtain tag for vhost_scsi_cmd\n");
 		return ERR_PTR(-ENOMEM);
 	}
 
-	cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[tag];
+	cmd = &svq->scsi_cmds[tag];
 	sg = cmd->tvc_sgl;
 	prot_sg = cmd->tvc_prot_sgl;
 	pages = cmd->tvc_upages;
@@ -1065,11 +1069,11 @@  static void vhost_scsi_submission_work(struct work_struct *work)
 				scsi_command_size(cdb), VHOST_SCSI_MAX_CDB_SIZE);
 				goto err;
 		}
-		cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
+		cmd = vhost_scsi_get_cmd(vq, tpg, cdb, tag, lun, task_attr,
 					 exp_data_len + prot_bytes,
 					 data_direction);
 		if (IS_ERR(cmd)) {
-			vq_err(vq, "vhost_scsi_get_tag failed %ld\n",
+			vq_err(vq, "vhost_scsi_get_cmd failed %ld\n",
 			       PTR_ERR(cmd));
 			goto err;
 		}
@@ -1373,6 +1377,83 @@  static void vhost_scsi_flush(struct vhost_scsi *vs)
 		wait_for_completion(&old_inflight[i]->comp);
 }
 
+static void vhost_scsi_destroy_vq_cmds(struct vhost_virtqueue *vq)
+{
+	struct vhost_scsi_virtqueue *svq = container_of(vq,
+					struct vhost_scsi_virtqueue, vq);
+	struct vhost_scsi_cmd *tv_cmd;
+	unsigned int i;
+
+	if (!svq->scsi_cmds)
+		return;
+
+	for (i = 0; i < svq->max_cmds; i++) {
+		tv_cmd = &svq->scsi_cmds[i];
+
+		kfree(tv_cmd->tvc_sgl);
+		kfree(tv_cmd->tvc_prot_sgl);
+		kfree(tv_cmd->tvc_upages);
+	}
+
+	sbitmap_free(&svq->scsi_tags);
+	kfree(svq->scsi_cmds);
+	svq->scsi_cmds = NULL;
+}
+
+static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds)
+{
+	struct vhost_scsi_virtqueue *svq = container_of(vq,
+					struct vhost_scsi_virtqueue, vq);
+	struct vhost_scsi_cmd *tv_cmd;
+	unsigned int i;
+
+	if (svq->scsi_cmds)
+		return 0;
+
+	if (sbitmap_init_node(&svq->scsi_tags, max_cmds, -1, GFP_KERNEL,
+			      NUMA_NO_NODE))
+		return -ENOMEM;
+	svq->max_cmds = max_cmds;
+
+	svq->scsi_cmds = kcalloc(max_cmds, sizeof(*tv_cmd), GFP_KERNEL);
+	if (!svq->scsi_cmds) {
+		sbitmap_free(&svq->scsi_tags);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < max_cmds; i++) {
+		tv_cmd = &svq->scsi_cmds[i];
+
+		tv_cmd->tvc_sgl = kcalloc(VHOST_SCSI_PREALLOC_SGLS,
+					  sizeof(struct scatterlist),
+					  GFP_KERNEL);
+		if (!tv_cmd->tvc_sgl) {
+			pr_err("Unable to allocate tv_cmd->tvc_sgl\n");
+			goto out;
+		}
+
+		tv_cmd->tvc_upages = kcalloc(VHOST_SCSI_PREALLOC_UPAGES,
+					     sizeof(struct page *),
+					     GFP_KERNEL);
+		if (!tv_cmd->tvc_upages) {
+			pr_err("Unable to allocate tv_cmd->tvc_upages\n");
+			goto out;
+		}
+
+		tv_cmd->tvc_prot_sgl = kcalloc(VHOST_SCSI_PREALLOC_PROT_SGLS,
+					       sizeof(struct scatterlist),
+					       GFP_KERNEL);
+		if (!tv_cmd->tvc_prot_sgl) {
+			pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");
+			goto out;
+		}
+	}
+	return 0;
+out:
+	vhost_scsi_destroy_vq_cmds(vq);
+	return -ENOMEM;
+}
+
 /*
  * Called from vhost_scsi_ioctl() context to walk the list of available
  * vhost_scsi_tpg with an active struct vhost_scsi_nexus
@@ -1427,10 +1508,9 @@  static void vhost_scsi_flush(struct vhost_scsi *vs)
 
 		if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) {
 			if (vs->vs_tpg && vs->vs_tpg[tpg->tport_tpgt]) {
-				kfree(vs_tpg);
 				mutex_unlock(&tpg->tv_tpg_mutex);
 				ret = -EEXIST;
-				goto out;
+				goto undepend;
 			}
 			/*
 			 * In order to ensure individual vhost-scsi configfs
@@ -1442,9 +1522,8 @@  static void vhost_scsi_flush(struct vhost_scsi *vs)
 			ret = target_depend_item(&se_tpg->tpg_group.cg_item);
 			if (ret) {
 				pr_warn("target_depend_item() failed: %d\n", ret);
-				kfree(vs_tpg);
 				mutex_unlock(&tpg->tv_tpg_mutex);
-				goto out;
+				goto undepend;
 			}
 			tpg->tv_tpg_vhost_count++;
 			tpg->vhost_scsi = vs;
@@ -1457,6 +1536,16 @@  static void vhost_scsi_flush(struct vhost_scsi *vs)
 	if (match) {
 		memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn,
 		       sizeof(vs->vs_vhost_wwpn));
+
+		for (i = VHOST_SCSI_VQ_IO; i < VHOST_SCSI_MAX_VQ; i++) {
+			vq = &vs->vqs[i].vq;
+			if (!vhost_vq_is_setup(vq))
+				continue;
+
+			if (vhost_scsi_setup_vq_cmds(vq, vq->num))
+				goto destroy_vq_cmds;
+		}
+
 		for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) {
 			vq = &vs->vqs[i].vq;
 			mutex_lock(&vq->mutex);
@@ -1476,7 +1565,22 @@  static void vhost_scsi_flush(struct vhost_scsi *vs)
 	vhost_scsi_flush(vs);
 	kfree(vs->vs_tpg);
 	vs->vs_tpg = vs_tpg;
+	goto out;
 
+destroy_vq_cmds:
+	for (i--; i >= VHOST_SCSI_VQ_IO; i--) {
+		if (!vhost_vq_get_backend(&vs->vqs[i].vq))
+			vhost_scsi_destroy_vq_cmds(&vs->vqs[i].vq);
+	}
+undepend:
+	for (i = 0; i < VHOST_SCSI_MAX_TARGET; i++) {
+		tpg = vs_tpg[i];
+		if (tpg) {
+			tpg->tv_tpg_vhost_count--;
+			target_undepend_item(&tpg->se_tpg.tpg_group.cg_item);
+		}
+	}
+	kfree(vs_tpg);
 out:
 	mutex_unlock(&vs->dev.mutex);
 	mutex_unlock(&vhost_scsi_mutex);
@@ -1549,6 +1653,12 @@  static void vhost_scsi_flush(struct vhost_scsi *vs)
 			mutex_lock(&vq->mutex);
 			vhost_vq_set_backend(vq, NULL);
 			mutex_unlock(&vq->mutex);
+			/*
+			 * Make sure cmds are not running before tearing them
+			 * down.
+			 */
+			vhost_scsi_flush(vs);
+			vhost_scsi_destroy_vq_cmds(vq);
 		}
 	}
 	/*
@@ -1842,23 +1952,6 @@  static void vhost_scsi_port_unlink(struct se_portal_group *se_tpg,
 	mutex_unlock(&vhost_scsi_mutex);
 }
 
-static void vhost_scsi_free_cmd_map_res(struct se_session *se_sess)
-{
-	struct vhost_scsi_cmd *tv_cmd;
-	unsigned int i;
-
-	if (!se_sess->sess_cmd_map)
-		return;
-
-	for (i = 0; i < VHOST_SCSI_DEFAULT_TAGS; i++) {
-		tv_cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[i];
-
-		kfree(tv_cmd->tvc_sgl);
-		kfree(tv_cmd->tvc_prot_sgl);
-		kfree(tv_cmd->tvc_upages);
-	}
-}
-
 static ssize_t vhost_scsi_tpg_attrib_fabric_prot_type_store(
 		struct config_item *item, const char *page, size_t count)
 {
@@ -1898,45 +1991,6 @@  static ssize_t vhost_scsi_tpg_attrib_fabric_prot_type_show(
 	NULL,
 };
 
-static int vhost_scsi_nexus_cb(struct se_portal_group *se_tpg,
-			       struct se_session *se_sess, void *p)
-{
-	struct vhost_scsi_cmd *tv_cmd;
-	unsigned int i;
-
-	for (i = 0; i < VHOST_SCSI_DEFAULT_TAGS; i++) {
-		tv_cmd = &((struct vhost_scsi_cmd *)se_sess->sess_cmd_map)[i];
-
-		tv_cmd->tvc_sgl = kcalloc(VHOST_SCSI_PREALLOC_SGLS,
-					  sizeof(struct scatterlist),
-					  GFP_KERNEL);
-		if (!tv_cmd->tvc_sgl) {
-			pr_err("Unable to allocate tv_cmd->tvc_sgl\n");
-			goto out;
-		}
-
-		tv_cmd->tvc_upages = kcalloc(VHOST_SCSI_PREALLOC_UPAGES,
-					     sizeof(struct page *),
-					     GFP_KERNEL);
-		if (!tv_cmd->tvc_upages) {
-			pr_err("Unable to allocate tv_cmd->tvc_upages\n");
-			goto out;
-		}
-
-		tv_cmd->tvc_prot_sgl = kcalloc(VHOST_SCSI_PREALLOC_PROT_SGLS,
-					       sizeof(struct scatterlist),
-					       GFP_KERNEL);
-		if (!tv_cmd->tvc_prot_sgl) {
-			pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");
-			goto out;
-		}
-	}
-	return 0;
-out:
-	vhost_scsi_free_cmd_map_res(se_sess);
-	return -ENOMEM;
-}
-
 static int vhost_scsi_make_nexus(struct vhost_scsi_tpg *tpg,
 				const char *name)
 {
@@ -1960,12 +2014,9 @@  static int vhost_scsi_make_nexus(struct vhost_scsi_tpg *tpg,
 	 * struct se_node_acl for the vhost_scsi struct se_portal_group with
 	 * the SCSI Initiator port name of the passed configfs group 'name'.
 	 */
-	tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg,
-					VHOST_SCSI_DEFAULT_TAGS,
-					sizeof(struct vhost_scsi_cmd),
+	tv_nexus->tvn_se_sess = target_setup_session(&tpg->se_tpg, 0, 0,
 					TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS,
-					(unsigned char *)name, tv_nexus,
-					vhost_scsi_nexus_cb);
+					(unsigned char *)name, tv_nexus, NULL);
 	if (IS_ERR(tv_nexus->tvn_se_sess)) {
 		mutex_unlock(&tpg->tv_tpg_mutex);
 		kfree(tv_nexus);
@@ -2015,7 +2066,6 @@  static int vhost_scsi_drop_nexus(struct vhost_scsi_tpg *tpg)
 		" %s Initiator Port: %s\n", vhost_scsi_dump_proto_id(tpg->tport),
 		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
 
-	vhost_scsi_free_cmd_map_res(se_sess);
 	/*
 	 * Release the SCSI I_T Nexus to the emulated vhost Target Port
 	 */