Revert the patch mentioned in the subject since it blocks I/O after
module unload has started while this is a legitimate use case. For e.g.
blktests test case srp/001 that patch causes a command timeout to be
triggered for the following call stack:
__schedule+0x4c3/0xd20
schedule+0x82/0x110
schedule_timeout+0x122/0x200
io_schedule_timeout+0x7b/0xc0
__wait_for_common+0x2bc/0x380
wait_for_completion_io_timeout+0x1d/0x20
blk_execute_rq+0x1db/0x200
__scsi_execute+0x1fb/0x310
sd_sync_cache+0x155/0x2c0 [sd_mod]
sd_shutdown+0xbb/0x190 [sd_mod]
sd_remove+0x5b/0x80 [sd_mod]
device_remove+0x9a/0xb0
device_release_driver_internal+0x2c5/0x360
device_release_driver+0x12/0x20
bus_remove_device+0x1aa/0x270
device_del+0x2d4/0x640
__scsi_remove_device+0x168/0x1a0
scsi_forget_host+0xa8/0xb0
scsi_remove_host+0x9b/0x150
sdebug_driver_remove+0x3d/0x140 [scsi_debug]
device_remove+0x6f/0xb0
device_release_driver_internal+0x2c5/0x360
device_release_driver+0x12/0x20
bus_remove_device+0x1aa/0x270
device_del+0x2d4/0x640
device_unregister+0x18/0x70
sdebug_do_remove_host+0x138/0x180 [scsi_debug]
scsi_debug_exit+0x45/0xd5 [scsi_debug]
__do_sys_delete_module.constprop.0+0x210/0x320
__x64_sys_delete_module+0x1f/0x30
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Reported-by: Yi Zhang <yi.zhang@xxxxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: Yi Zhang <yi.zhang@xxxxxxxxxx>
Cc: Bob Pearson <rpearsonhpe@xxxxxxxxx>
Fixes: 2aad3cd85370 ("scsi: scsi_debug: Address races following module load"; )
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/scsi/scsi_debug.c | 197 ++++++++++----------------------------
1 file changed, 51 insertions(+), 146 deletions(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index c607755cce00..db6f4b96606c 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -32,7 +32,6 @@
#include <linux/blkdev.h>
#include <linux/crc-t10dif.h>
#include <linux/spinlock.h>
-#include <linux/mutex.h>
#include <linux/interrupt.h>
#include <linux/atomic.h>
#include <linux/hrtimer.h>
@@ -732,9 +731,7 @@ static const struct opcode_info_t opcode_info_arr[SDEB_I_LAST_ELEM_P1 + 1] = {
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
};
-static atomic_t sdebug_num_hosts;
-static DEFINE_MUTEX(add_host_mutex);
-
+static int sdebug_num_hosts;
static int sdebug_add_host = DEF_NUM_HOST; /* in sysfs this is relative */
static int sdebug_ato = DEF_ATO;
static int sdebug_cdb_len = DEF_CDB_LEN;
@@ -781,7 +778,6 @@ static int sdebug_uuid_ctl = DEF_UUID_CTL;
static bool sdebug_random = DEF_RANDOM;
static bool sdebug_per_host_store = DEF_PER_HOST_STORE;
static bool sdebug_removable = DEF_REMOVABLE;
-static bool sdebug_deflect_incoming;
static bool sdebug_clustering;
static bool sdebug_host_lock = DEF_HOST_LOCK;
static bool sdebug_strict = DEF_STRICT;
@@ -5122,10 +5118,6 @@ static int scsi_debug_slave_configure(struct scsi_device *sdp)
sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
if (sdp->host->max_cmd_len != SDEBUG_MAX_CMD_LEN)
sdp->host->max_cmd_len = SDEBUG_MAX_CMD_LEN;
- if (smp_load_acquire(&sdebug_deflect_incoming)) {
- pr_info("Exit early due to deflect_incoming\n");
- return 1;
- }
if (devip == NULL) {
devip = find_build_dev_info(sdp);
if (devip == NULL)
@@ -5211,7 +5203,7 @@ static bool stop_queued_cmnd(struct scsi_cmnd *cmnd)
}
/* Deletes (stops) timers or work queues of all queued commands */
-static void stop_all_queued(bool done_with_no_conn)
+static void stop_all_queued(void)
{
unsigned long iflags;
int j, k;
@@ -5220,15 +5212,13 @@ static void stop_all_queued(bool done_with_no_conn)
struct sdebug_queued_cmd *sqcp;
struct sdebug_dev_info *devip;
struct sdebug_defer *sd_dp;
- struct scsi_cmnd *scp;
for (j = 0, sqp = sdebug_q_arr; j < submit_queues; ++j, ++sqp) {
spin_lock_irqsave(&sqp->qc_lock, iflags);
for (k = 0; k < SDEBUG_CANQUEUE; ++k) {
if (test_bit(k, sqp->in_use_bm)) {
sqcp = &sqp->qc_arr[k];
- scp = sqcp->a_cmnd;
- if (!scp)
+ if (sqcp->a_cmnd == NULL)
continue;
devip = (struct sdebug_dev_info *)
sqcp->a_cmnd->device->hostdata;
@@ -5243,10 +5233,6 @@ static void stop_all_queued(bool done_with_no_conn)
l_defer_t = SDEB_DEFER_NONE;
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
stop_qc_helper(sd_dp, l_defer_t);
- if (done_with_no_conn && l_defer_t != SDEB_DEFER_NONE) {
- scp->result = DID_NO_CONNECT << 16;
- scsi_done(scp);
- }
clear_bit(k, sqp->in_use_bm);
spin_lock_irqsave(&sqp->qc_lock, iflags);
}
@@ -5389,7 +5375,7 @@ static int scsi_debug_host_reset(struct scsi_cmnd *SCpnt)
}
}
spin_unlock(&sdebug_host_list_lock);
- stop_all_queued(false);
+ stop_all_queued();
if (SDEBUG_OPT_RESET_NOISE & sdebug_opts)
sdev_printk(KERN_INFO, SCpnt->device,
"%s: %d device(s) found\n", __func__, k);
@@ -5449,50 +5435,13 @@ static void sdebug_build_parts(unsigned char *ramp, unsigned long store_size)
}
}
-static void sdeb_block_all_queues(void)
-{
- int j;
- struct sdebug_queue *sqp;
-
- for (j = 0, sqp = sdebug_q_arr; j < submit_queues; ++j, ++sqp)
- atomic_set(&sqp->blocked, (int)true);
-}
-
-static void sdeb_unblock_all_queues(void)
+static void block_unblock_all_queues(bool block)
{
int j;
struct sdebug_queue *sqp;
for (j = 0, sqp = sdebug_q_arr; j < submit_queues; ++j, ++sqp)
- atomic_set(&sqp->blocked, (int)false);
-}
-
-static void
-sdeb_add_n_hosts(int num_hosts)
-{
- if (num_hosts < 1)
- return;
- do {
- bool found;
- unsigned long idx;
- struct sdeb_store_info *sip;
- bool want_phs = (sdebug_fake_rw == 0) && sdebug_per_host_store;
-
- found = false;
- if (want_phs) {
- xa_for_each_marked(per_store_ap, idx, sip, SDEB_XA_NOT_IN_USE) {
- sdeb_most_recent_idx = (int)idx;
- found = true;
- break;
- }
- if (found) /* re-use case */
- sdebug_add_host_helper((int)idx);
- else
- sdebug_do_add_host(true /* make new store */);
- } else {
- sdebug_do_add_host(false);
- }
- } while (--num_hosts);
+ atomic_set(&sqp->blocked, (int)block);
}
/* Adjust (by rounding down) the sdebug_cmnd_count so abs(every_nth)-1
@@ -5505,10 +5454,10 @@ static void tweak_cmnd_count(void)
modulo = abs(sdebug_every_nth);
if (modulo < 2)
return;
- sdeb_block_all_queues();
+ block_unblock_all_queues(true);
count = atomic_read(&sdebug_cmnd_count);
atomic_set(&sdebug_cmnd_count, (count / modulo) * modulo);
- sdeb_unblock_all_queues();
+ block_unblock_all_queues(false);
}
static void clear_queue_stats(void)
@@ -5526,15 +5475,6 @@ static bool inject_on_this_cmd(void)
return (atomic_read(&sdebug_cmnd_count) % abs(sdebug_every_nth)) == 0;
}
-static int process_deflect_incoming(struct scsi_cmnd *scp)
-{
- u8 opcode = scp->cmnd[0];
-
- if (opcode == SYNCHRONIZE_CACHE || opcode == SYNCHRONIZE_CACHE_16)
- return 0;
- return DID_NO_CONNECT << 16;
-}
-
#define INCLUSIVE_TIMING_MAX_NS 1000000 /* 1 millisecond */
/* Complete the processing of the thread that queued a SCSI command to this
@@ -5544,7 +5484,8 @@ static int process_deflect_incoming(struct scsi_cmnd *scp)
*/
static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
int scsi_result,
- int (*pfp)(struct scsi_cmnd *, struct sdebug_dev_info *),
+ int (*pfp)(struct scsi_cmnd *,
+ struct sdebug_dev_info *),
int delta_jiff, int ndelay)
{
bool new_sd_dp;
@@ -5565,27 +5506,13 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
}
sdp = cmnd->device;
- if (delta_jiff == 0) {
- sqp = get_queue(cmnd);
- if (atomic_read(&sqp->blocked)) {
- if (smp_load_acquire(&sdebug_deflect_incoming))
- return process_deflect_incoming(cmnd);
- else
- return SCSI_MLQUEUE_HOST_BUSY;
- }
+ if (delta_jiff == 0)
goto respond_in_thread;
- }
sqp = get_queue(cmnd);
spin_lock_irqsave(&sqp->qc_lock, iflags);
if (unlikely(atomic_read(&sqp->blocked))) {
spin_unlock_irqrestore(&sqp->qc_lock, iflags);
- if (smp_load_acquire(&sdebug_deflect_incoming)) {
- scsi_result = process_deflect_incoming(cmnd);
- goto respond_in_thread;
- }
- if (sdebug_verbose)
- pr_info("blocked --> SCSI_MLQUEUE_HOST_BUSY\n");
return SCSI_MLQUEUE_HOST_BUSY;
}
num_in_q = atomic_read(&devip->num_in_q);
@@ -5774,12 +5701,8 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
respond_in_thread: /* call back to mid-layer using invocation thread */
cmnd->result = pfp != NULL ? pfp(cmnd, devip) : 0;
cmnd->result &= ~SDEG_RES_IMMED_MASK;
- if (cmnd->result == 0 && scsi_result != 0) {
+ if (cmnd->result == 0 && scsi_result != 0)
cmnd->result = scsi_result;
- if (sdebug_verbose)
- pr_info("respond_in_thread: tag=0x%x, scp->result=0x%x\n",
- blk_mq_unique_tag(scsi_cmd_to_rq(cmnd)), scsi_result);
- }
scsi_done(cmnd);
return 0;
}
@@ -6064,7 +5987,7 @@ static ssize_t delay_store(struct device_driver *ddp, const char *buf,
int j, k;
struct sdebug_queue *sqp;
- sdeb_block_all_queues();
+ block_unblock_all_queues(true);
for (j = 0, sqp = sdebug_q_arr; j < submit_queues;
++j, ++sqp) {
k = find_first_bit(sqp->in_use_bm,
@@ -6078,7 +6001,7 @@ static ssize_t delay_store(struct device_driver *ddp, const char *buf,
sdebug_jdelay = jdelay;
sdebug_ndelay = 0;
}
- sdeb_unblock_all_queues();
+ block_unblock_all_queues(false);
}
return res;
}
@@ -6104,7 +6027,7 @@ static ssize_t ndelay_store(struct device_driver *ddp, const char *buf,
int j, k;
struct sdebug_queue *sqp;
- sdeb_block_all_queues();
+ block_unblock_all_queues(true);
for (j = 0, sqp = sdebug_q_arr; j < submit_queues;
++j, ++sqp) {
k = find_first_bit(sqp->in_use_bm,
@@ -6119,7 +6042,7 @@ static ssize_t ndelay_store(struct device_driver *ddp, const char *buf,
sdebug_jdelay = ndelay ? JDELAY_OVERRIDDEN
: DEF_JDELAY;
}
- sdeb_unblock_all_queues();
+ block_unblock_all_queues(false);
}
return res;
}
@@ -6433,7 +6356,7 @@ static ssize_t max_queue_store(struct device_driver *ddp, const char *buf,
if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n > 0) &&
(n <= SDEBUG_CANQUEUE) &&
(sdebug_host_max_queue == 0)) {
- sdeb_block_all_queues();
+ block_unblock_all_queues(true);
k = 0;
for (j = 0, sqp = sdebug_q_arr; j < submit_queues;
++j, ++sqp) {
@@ -6448,7 +6371,7 @@ static ssize_t max_queue_store(struct device_driver *ddp, const char *buf,
atomic_set(&retired_max_queue, k + 1);
else
atomic_set(&retired_max_queue, 0);
- sdeb_unblock_all_queues();
+ block_unblock_all_queues(false);
return count;
}
return -EINVAL;
@@ -6537,48 +6460,43 @@ static DRIVER_ATTR_RW(virtual_gb);
static ssize_t add_host_show(struct device_driver *ddp, char *buf)
{
/* absolute number of hosts currently active is what is shown */
- return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&sdebug_num_hosts));
+ return scnprintf(buf, PAGE_SIZE, "%d\n", sdebug_num_hosts);
}
-/*
- * Accept positive and negative values. Hex values (only positive) may be prefixed by '0x'.
- * To remove all hosts use a large negative number (e.g. -9999). The value 0 does nothing.
- * Returns -EBUSY if another add_host sysfs invocation is active.
- */
static ssize_t add_host_store(struct device_driver *ddp, const char *buf,
size_t count)
{
+ bool found;
+ unsigned long idx;
+ struct sdeb_store_info *sip;
+ bool want_phs = (sdebug_fake_rw == 0) && sdebug_per_host_store;
int delta_hosts;
- if (count == 0 || kstrtoint(buf, 0, &delta_hosts))
+ if (sscanf(buf, "%d", &delta_hosts) != 1)
return -EINVAL;
- if (sdebug_verbose)
- pr_info("prior num_hosts=%d, num_to_add=%d\n",
- atomic_read(&sdebug_num_hosts), delta_hosts);
- if (delta_hosts == 0)
- return count;
- if (mutex_trylock(&add_host_mutex) == 0)
- return -EBUSY;
if (delta_hosts > 0) {
- sdeb_add_n_hosts(delta_hosts);
- } else if (delta_hosts < 0) {
- smp_store_release(&sdebug_deflect_incoming, true);
- sdeb_block_all_queues();
- if (delta_hosts >= atomic_read(&sdebug_num_hosts))
- stop_all_queued(true);
do {
- if (atomic_read(&sdebug_num_hosts) < 1) {
- free_all_queued();
- break;
+ found = false;
+ if (want_phs) {
+ xa_for_each_marked(per_store_ap, idx, sip,
+ SDEB_XA_NOT_IN_USE) {
+ sdeb_most_recent_idx = (int)idx;
+ found = true;
+ break;
+ }
+ if (found) /* re-use case */
+ sdebug_add_host_helper((int)idx);
+ else
+ sdebug_do_add_host(true);
+ } else {
+ sdebug_do_add_host(false);
}
+ } while (--delta_hosts);
+ } else if (delta_hosts < 0) {
+ do {
sdebug_do_remove_host(false);
} while (++delta_hosts);
- sdeb_unblock_all_queues();
- smp_store_release(&sdebug_deflect_incoming, false);
}
- mutex_unlock(&add_host_mutex);
- if (sdebug_verbose)
- pr_info("post num_hosts=%d\n", atomic_read(&sdebug_num_hosts));
return count;
}
static DRIVER_ATTR_RW(add_host);
@@ -7089,10 +7007,6 @@ static int __init scsi_debug_init(void)
sdebug_add_host = 0;
for (k = 0; k < hosts_to_add; k++) {
- if (smp_load_acquire(&sdebug_deflect_incoming)) {
- pr_info("exit early as sdebug_deflect_incoming is set\n");
- return 0;
- }
if (want_store && k == 0) {
ret = sdebug_add_host_helper(idx);
if (ret < 0) {
@@ -7110,12 +7024,8 @@ static int __init scsi_debug_init(void)
}
}
if (sdebug_verbose)
- pr_info("built %d host(s)\n", atomic_read(&sdebug_num_hosts));
+ pr_info("built %d host(s)\n", sdebug_num_hosts);
- /*
- * Even though all the hosts have been established, due to async device (LU) scanning
- * by the scsi mid-level, there may still be devices (LUs) being set up.
- */
return 0;
bus_unreg:
@@ -7131,17 +7041,12 @@ static int __init scsi_debug_init(void)
static void __exit scsi_debug_exit(void)
{
- int k;
+ int k = sdebug_num_hosts;
- /* Possible race with LUs still being set up; stop them asap */
- sdeb_block_all_queues();
- smp_store_release(&sdebug_deflect_incoming, true);
- stop_all_queued(false);
- for (k = 0; atomic_read(&sdebug_num_hosts) > 0; k++)
+ stop_all_queued();
+ for (; k; k--)
sdebug_do_remove_host(true);
free_all_queued();
- if (sdebug_verbose)
- pr_info("removed %d hosts\n", k);
driver_unregister(&sdebug_driverfs_driver);
bus_unregister(&pseudo_lld_bus);
root_device_unregister(pseudo_primary);
@@ -7311,13 +7216,13 @@ static int sdebug_add_host_helper(int per_host_idx)
sdbg_host->dev.bus = &pseudo_lld_bus;
sdbg_host->dev.parent = pseudo_primary;
sdbg_host->dev.release = &sdebug_release_adapter;
- dev_set_name(&sdbg_host->dev, "adapter%d", atomic_read(&sdebug_num_hosts));
+ dev_set_name(&sdbg_host->dev, "adapter%d", sdebug_num_hosts);
error = device_register(&sdbg_host->dev);
if (error)
goto clean;
- atomic_inc(&sdebug_num_hosts);
+ ++sdebug_num_hosts;
return 0;
clean:
@@ -7381,7 +7286,7 @@ static void sdebug_do_remove_host(bool the_end)
return;
device_unregister(&sdbg_host->dev);
- atomic_dec(&sdebug_num_hosts);
+ --sdebug_num_hosts;
}
static int sdebug_change_qdepth(struct scsi_device *sdev, int qdepth)
@@ -7389,10 +7294,10 @@ static int sdebug_change_qdepth(struct scsi_device *sdev, int qdepth)
int num_in_q = 0;
struct sdebug_dev_info *devip;
- sdeb_block_all_queues();
+ block_unblock_all_queues(true);
devip = (struct sdebug_dev_info *)sdev->hostdata;
if (NULL == devip) {
- sdeb_unblock_all_queues();
+ block_unblock_all_queues(false);
return -ENODEV;
}
num_in_q = atomic_read(&devip->num_in_q);
@@ -7411,7 +7316,7 @@ static int sdebug_change_qdepth(struct scsi_device *sdev, int qdepth)
sdev_printk(KERN_INFO, sdev, "%s: qdepth=%d, num_in_q=%d\n",
__func__, qdepth, num_in_q);
}
- sdeb_unblock_all_queues();
+ block_unblock_all_queues(false);
return sdev->queue_depth;
}
