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Diffstat (limited to 'drivers/scsi/scsi.c')
-rw-r--r--drivers/scsi/scsi.c282
1 files changed, 168 insertions, 114 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 0fb1709ce5e..1a9fba6a9f9 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -122,6 +122,11 @@ static const char *const scsi_device_types[] = {
"Automation/Drive ",
};
+/**
+ * scsi_device_type - Return 17 char string indicating device type.
+ * @type: type number to look up
+ */
+
const char * scsi_device_type(unsigned type)
{
if (type == 0x1e)
@@ -136,32 +141,45 @@ const char * scsi_device_type(unsigned type)
EXPORT_SYMBOL(scsi_device_type);
struct scsi_host_cmd_pool {
- struct kmem_cache *slab;
- unsigned int users;
- char *name;
- unsigned int slab_flags;
- gfp_t gfp_mask;
+ struct kmem_cache *cmd_slab;
+ struct kmem_cache *sense_slab;
+ unsigned int users;
+ char *cmd_name;
+ char *sense_name;
+ unsigned int slab_flags;
+ gfp_t gfp_mask;
};
static struct scsi_host_cmd_pool scsi_cmd_pool = {
- .name = "scsi_cmd_cache",
+ .cmd_name = "scsi_cmd_cache",
+ .sense_name = "scsi_sense_cache",
.slab_flags = SLAB_HWCACHE_ALIGN,
};
static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
- .name = "scsi_cmd_cache(DMA)",
+ .cmd_name = "scsi_cmd_cache(DMA)",
+ .sense_name = "scsi_sense_cache(DMA)",
.slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
.gfp_mask = __GFP_DMA,
};
static DEFINE_MUTEX(host_cmd_pool_mutex);
+/**
+ * __scsi_get_command - Allocate a struct scsi_cmnd
+ * @shost: host to transmit command
+ * @gfp_mask: allocation mask
+ *
+ * Description: allocate a struct scsi_cmd from host's slab, recycling from the
+ * host's free_list if necessary.
+ */
struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
{
struct scsi_cmnd *cmd;
+ unsigned char *buf;
- cmd = kmem_cache_alloc(shost->cmd_pool->slab,
- gfp_mask | shost->cmd_pool->gfp_mask);
+ cmd = kmem_cache_alloc(shost->cmd_pool->cmd_slab,
+ gfp_mask | shost->cmd_pool->gfp_mask);
if (unlikely(!cmd)) {
unsigned long flags;
@@ -173,19 +191,32 @@ struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
list_del_init(&cmd->list);
}
spin_unlock_irqrestore(&shost->free_list_lock, flags);
+
+ if (cmd) {
+ buf = cmd->sense_buffer;
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->sense_buffer = buf;
+ }
+ } else {
+ buf = kmem_cache_alloc(shost->cmd_pool->sense_slab,
+ gfp_mask | shost->cmd_pool->gfp_mask);
+ if (likely(buf)) {
+ memset(cmd, 0, sizeof(*cmd));
+ cmd->sense_buffer = buf;
+ } else {
+ kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
+ cmd = NULL;
+ }
}
return cmd;
}
EXPORT_SYMBOL_GPL(__scsi_get_command);
-/*
- * Function: scsi_get_command()
- *
- * Purpose: Allocate and setup a scsi command block
- *
- * Arguments: dev - parent scsi device
- * gfp_mask- allocator flags
+/**
+ * scsi_get_command - Allocate and setup a scsi command block
+ * @dev: parent scsi device
+ * @gfp_mask: allocator flags
*
* Returns: The allocated scsi command structure.
*/
@@ -202,7 +233,6 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
if (likely(cmd != NULL)) {
unsigned long flags;
- memset(cmd, 0, sizeof(*cmd));
cmd->device = dev;
init_timer(&cmd->eh_timeout);
INIT_LIST_HEAD(&cmd->list);
@@ -217,6 +247,12 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
}
EXPORT_SYMBOL(scsi_get_command);
+/**
+ * __scsi_put_command - Free a struct scsi_cmnd
+ * @shost: dev->host
+ * @cmd: Command to free
+ * @dev: parent scsi device
+ */
void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
struct device *dev)
{
@@ -230,19 +266,19 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
}
spin_unlock_irqrestore(&shost->free_list_lock, flags);
- if (likely(cmd != NULL))
- kmem_cache_free(shost->cmd_pool->slab, cmd);
+ if (likely(cmd != NULL)) {
+ kmem_cache_free(shost->cmd_pool->sense_slab,
+ cmd->sense_buffer);
+ kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
+ }
put_device(dev);
}
EXPORT_SYMBOL(__scsi_put_command);
-/*
- * Function: scsi_put_command()
- *
- * Purpose: Free a scsi command block
- *
- * Arguments: cmd - command block to free
+/**
+ * scsi_put_command - Free a scsi command block
+ * @cmd: command block to free
*
* Returns: Nothing.
*
@@ -263,12 +299,13 @@ void scsi_put_command(struct scsi_cmnd *cmd)
}
EXPORT_SYMBOL(scsi_put_command);
-/*
- * Function: scsi_setup_command_freelist()
- *
- * Purpose: Setup the command freelist for a scsi host.
+/**
+ * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
+ * @shost: host to allocate the freelist for.
*
- * Arguments: shost - host to allocate the freelist for.
+ * Description: The command freelist protects against system-wide out of memory
+ * deadlock by preallocating one SCSI command structure for each host, so the
+ * system can always write to a swap file on a device associated with that host.
*
* Returns: Nothing.
*/
@@ -282,16 +319,24 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
/*
* Select a command slab for this host and create it if not
- * yet existant.
+ * yet existent.
*/
mutex_lock(&host_cmd_pool_mutex);
pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
if (!pool->users) {
- pool->slab = kmem_cache_create(pool->name,
- sizeof(struct scsi_cmnd), 0,
- pool->slab_flags, NULL);
- if (!pool->slab)
+ pool->cmd_slab = kmem_cache_create(pool->cmd_name,
+ sizeof(struct scsi_cmnd), 0,
+ pool->slab_flags, NULL);
+ if (!pool->cmd_slab)
+ goto fail;
+
+ pool->sense_slab = kmem_cache_create(pool->sense_name,
+ SCSI_SENSE_BUFFERSIZE, 0,
+ pool->slab_flags, NULL);
+ if (!pool->sense_slab) {
+ kmem_cache_destroy(pool->cmd_slab);
goto fail;
+ }
}
pool->users++;
@@ -301,29 +346,36 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
/*
* Get one backup command for this host.
*/
- cmd = kmem_cache_alloc(shost->cmd_pool->slab,
- GFP_KERNEL | shost->cmd_pool->gfp_mask);
+ cmd = kmem_cache_alloc(shost->cmd_pool->cmd_slab,
+ GFP_KERNEL | shost->cmd_pool->gfp_mask);
if (!cmd)
goto fail2;
- list_add(&cmd->list, &shost->free_list);
+
+ cmd->sense_buffer = kmem_cache_alloc(shost->cmd_pool->sense_slab,
+ GFP_KERNEL |
+ shost->cmd_pool->gfp_mask);
+ if (!cmd->sense_buffer)
+ goto fail2;
+
+ list_add(&cmd->list, &shost->free_list);
return 0;
fail2:
- if (!--pool->users)
- kmem_cache_destroy(pool->slab);
- return -ENOMEM;
+ if (cmd)
+ kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
+ mutex_lock(&host_cmd_pool_mutex);
+ if (!--pool->users) {
+ kmem_cache_destroy(pool->cmd_slab);
+ kmem_cache_destroy(pool->sense_slab);
+ }
fail:
mutex_unlock(&host_cmd_pool_mutex);
return -ENOMEM;
-
}
-/*
- * Function: scsi_destroy_command_freelist()
- *
- * Purpose: Release the command freelist for a scsi host.
- *
- * Arguments: shost - host that's freelist is going to be destroyed
+/**
+ * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
+ * @shost: host whose freelist is going to be destroyed
*/
void scsi_destroy_command_freelist(struct Scsi_Host *shost)
{
@@ -332,12 +384,16 @@ void scsi_destroy_command_freelist(struct Scsi_Host *shost)
cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
list_del_init(&cmd->list);
- kmem_cache_free(shost->cmd_pool->slab, cmd);
+ kmem_cache_free(shost->cmd_pool->sense_slab,
+ cmd->sense_buffer);
+ kmem_cache_free(shost->cmd_pool->cmd_slab, cmd);
}
mutex_lock(&host_cmd_pool_mutex);
- if (!--shost->cmd_pool->users)
- kmem_cache_destroy(shost->cmd_pool->slab);
+ if (!--shost->cmd_pool->users) {
+ kmem_cache_destroy(shost->cmd_pool->cmd_slab);
+ kmem_cache_destroy(shost->cmd_pool->sense_slab);
+ }
mutex_unlock(&host_cmd_pool_mutex);
}
@@ -441,8 +497,12 @@ void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
}
#endif
-/*
- * Assign a serial number to the request for error recovery
+/**
+ * scsi_cmd_get_serial - Assign a serial number to a command
+ * @host: the scsi host
+ * @cmd: command to assign serial number to
+ *
+ * Description: a serial number identifies a request for error recovery
* and debugging purposes. Protected by the Host_Lock of host.
*/
static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
@@ -452,14 +512,12 @@ static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd
cmd->serial_number = host->cmd_serial_number++;
}
-/*
- * Function: scsi_dispatch_command
- *
- * Purpose: Dispatch a command to the low-level driver.
- *
- * Arguments: cmd - command block we are dispatching.
+/**
+ * scsi_dispatch_command - Dispatch a command to the low-level driver.
+ * @cmd: command block we are dispatching.
*
- * Notes:
+ * Return: nonzero return request was rejected and device's queue needs to be
+ * plugged.
*/
int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
{
@@ -585,7 +643,7 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
/**
* scsi_req_abort_cmd -- Request command recovery for the specified command
- * cmd: pointer to the SCSI command of interest
+ * @cmd: pointer to the SCSI command of interest
*
* This function requests that SCSI Core start recovery for the
* command by deleting the timer and adding the command to the eh
@@ -606,9 +664,9 @@ EXPORT_SYMBOL(scsi_req_abort_cmd);
* @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
* ownership back to SCSI Core -- i.e. the LLDD has finished with it.
*
- * This function is the mid-level's (SCSI Core) interrupt routine, which
- * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
- * the command to the done queue for further processing.
+ * Description: This function is the mid-level's (SCSI Core) interrupt routine,
+ * which regains ownership of the SCSI command (de facto) from a LLDD, and
+ * enqueues the command to the done queue for further processing.
*
* This is the producer of the done queue who enqueues at the tail.
*
@@ -617,7 +675,7 @@ EXPORT_SYMBOL(scsi_req_abort_cmd);
static void scsi_done(struct scsi_cmnd *cmd)
{
/*
- * We don't have to worry about this one timing out any more.
+ * We don't have to worry about this one timing out anymore.
* If we are unable to remove the timer, then the command
* has already timed out. In which case, we have no choice but to
* let the timeout function run, as we have no idea where in fact
@@ -660,10 +718,11 @@ static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
}
-/*
- * Function: scsi_finish_command
+/**
+ * scsi_finish_command - cleanup and pass command back to upper layer
+ * @cmd: the command
*
- * Purpose: Pass command off to upper layer for finishing of I/O
+ * Description: Pass command off to upper layer for finishing of I/O
* request, waking processes that are waiting on results,
* etc.
*/
@@ -708,18 +767,14 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
}
EXPORT_SYMBOL(scsi_finish_command);
-/*
- * Function: scsi_adjust_queue_depth()
- *
- * Purpose: Allow low level drivers to tell us to change the queue depth
- * on a specific SCSI device
- *
- * Arguments: sdev - SCSI Device in question
- * tagged - Do we use tagged queueing (non-0) or do we treat
- * this device as an untagged device (0)
- * tags - Number of tags allowed if tagged queueing enabled,
- * or number of commands the low level driver can
- * queue up in non-tagged mode (as per cmd_per_lun).
+/**
+ * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
+ * @sdev: SCSI Device in question
+ * @tagged: Do we use tagged queueing (non-0) or do we treat
+ * this device as an untagged device (0)
+ * @tags: Number of tags allowed if tagged queueing enabled,
+ * or number of commands the low level driver can
+ * queue up in non-tagged mode (as per cmd_per_lun).
*
* Returns: Nothing
*
@@ -742,8 +797,8 @@ void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
- /* Check to see if the queue is managed by the block layer
- * if it is, and we fail to adjust the depth, exit */
+ /* Check to see if the queue is managed by the block layer.
+ * If it is, and we fail to adjust the depth, exit. */
if (blk_queue_tagged(sdev->request_queue) &&
blk_queue_resize_tags(sdev->request_queue, tags) != 0)
goto out;
@@ -772,20 +827,17 @@ void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
}
EXPORT_SYMBOL(scsi_adjust_queue_depth);
-/*
- * Function: scsi_track_queue_full()
+/**
+ * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
+ * @sdev: SCSI Device in question
+ * @depth: Current number of outstanding SCSI commands on this device,
+ * not counting the one returned as QUEUE_FULL.
*
- * Purpose: This function will track successive QUEUE_FULL events on a
+ * Description: This function will track successive QUEUE_FULL events on a
* specific SCSI device to determine if and when there is a
* need to adjust the queue depth on the device.
*
- * Arguments: sdev - SCSI Device in question
- * depth - Current number of outstanding SCSI commands on
- * this device, not counting the one returned as
- * QUEUE_FULL.
- *
- * Returns: 0 - No change needed
- * >0 - Adjust queue depth to this new depth
+ * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
* -1 - Drop back to untagged operation using host->cmd_per_lun
* as the untagged command depth
*
@@ -824,10 +876,10 @@ int scsi_track_queue_full(struct scsi_device *sdev, int depth)
EXPORT_SYMBOL(scsi_track_queue_full);
/**
- * scsi_device_get - get an addition reference to a scsi_device
+ * scsi_device_get - get an additional reference to a scsi_device
* @sdev: device to get a reference to
*
- * Gets a reference to the scsi_device and increments the use count
+ * Description: Gets a reference to the scsi_device and increments the use count
* of the underlying LLDD module. You must hold host_lock of the
* parent Scsi_Host or already have a reference when calling this.
*/
@@ -849,8 +901,8 @@ EXPORT_SYMBOL(scsi_device_get);
* scsi_device_put - release a reference to a scsi_device
* @sdev: device to release a reference on.
*
- * Release a reference to the scsi_device and decrements the use count
- * of the underlying LLDD module. The device is freed once the last
+ * Description: Release a reference to the scsi_device and decrements the use
+ * count of the underlying LLDD module. The device is freed once the last
* user vanishes.
*/
void scsi_device_put(struct scsi_device *sdev)
@@ -867,7 +919,7 @@ void scsi_device_put(struct scsi_device *sdev)
}
EXPORT_SYMBOL(scsi_device_put);
-/* helper for shost_for_each_device, thus not documented */
+/* helper for shost_for_each_device, see that for documentation */
struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
struct scsi_device *prev)
{
@@ -895,6 +947,8 @@ EXPORT_SYMBOL(__scsi_iterate_devices);
/**
* starget_for_each_device - helper to walk all devices of a target
* @starget: target whose devices we want to iterate over.
+ * @data: Opaque passed to each function call.
+ * @fn: Function to call on each device
*
* This traverses over each device of @starget. The devices have
* a reference that must be released by scsi_host_put when breaking
@@ -946,13 +1000,13 @@ EXPORT_SYMBOL(__starget_for_each_device);
* @starget: SCSI target pointer
* @lun: SCSI Logical Unit Number
*
- * Looks up the scsi_device with the specified @lun for a give
- * @starget. The returned scsi_device does not have an additional
+ * Description: Looks up the scsi_device with the specified @lun for a given
+ * @starget. The returned scsi_device does not have an additional
* reference. You must hold the host's host_lock over this call and
* any access to the returned scsi_device.
*
- * Note: The only reason why drivers would want to use this is because
- * they're need to access the device list in irq context. Otherwise you
+ * Note: The only reason why drivers should use this is because
+ * they need to access the device list in irq context. Otherwise you
* really want to use scsi_device_lookup_by_target instead.
**/
struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
@@ -974,9 +1028,9 @@ EXPORT_SYMBOL(__scsi_device_lookup_by_target);
* @starget: SCSI target pointer
* @lun: SCSI Logical Unit Number
*
- * Looks up the scsi_device with the specified @channel, @id, @lun for a
- * give host. The returned scsi_device has an additional reference that
- * needs to be release with scsi_host_put once you're done with it.
+ * Description: Looks up the scsi_device with the specified @channel, @id, @lun
+ * for a given host. The returned scsi_device has an additional reference that
+ * needs to be released with scsi_device_put once you're done with it.
**/
struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
uint lun)
@@ -996,19 +1050,19 @@ struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
EXPORT_SYMBOL(scsi_device_lookup_by_target);
/**
- * scsi_device_lookup - find a device given the host (UNLOCKED)
+ * __scsi_device_lookup - find a device given the host (UNLOCKED)
* @shost: SCSI host pointer
* @channel: SCSI channel (zero if only one channel)
- * @pun: SCSI target number (physical unit number)
+ * @id: SCSI target number (physical unit number)
* @lun: SCSI Logical Unit Number
*
- * Looks up the scsi_device with the specified @channel, @id, @lun for a
- * give host. The returned scsi_device does not have an additional reference.
- * You must hold the host's host_lock over this call and any access to the
- * returned scsi_device.
+ * Description: Looks up the scsi_device with the specified @channel, @id, @lun
+ * for a given host. The returned scsi_device does not have an additional
+ * reference. You must hold the host's host_lock over this call and any access
+ * to the returned scsi_device.
*
* Note: The only reason why drivers would want to use this is because
- * they're need to access the device list in irq context. Otherwise you
+ * they need to access the device list in irq context. Otherwise you
* really want to use scsi_device_lookup instead.
**/
struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
@@ -1033,9 +1087,9 @@ EXPORT_SYMBOL(__scsi_device_lookup);
* @id: SCSI target number (physical unit number)
* @lun: SCSI Logical Unit Number
*
- * Looks up the scsi_device with the specified @channel, @id, @lun for a
- * give host. The returned scsi_device has an additional reference that
- * needs to be release with scsi_host_put once you're done with it.
+ * Description: Looks up the scsi_device with the specified @channel, @id, @lun
+ * for a given host. The returned scsi_device has an additional reference that
+ * needs to be released with scsi_device_put once you're done with it.
**/
struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
uint channel, uint id, uint lun)
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-03 11:10:30 +0000