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authorJames Bottomley <James.Bottomley@suse.de>2010-12-16 09:22:24 -0500
committerJames Bottomley <James.Bottomley@suse.de>2010-12-21 08:23:54 -0600
commit29687512c0b084957112cc2c0743ce34cd0d5055 (patch)
treedc44aff0b61e8bed3ea664c5a872d04bad8c4132 /Documentation/scsi
parent8816624222b12e5d7e291e9d1973fc42b994eb6b (diff)
downloadlinux-29687512c0b084957112cc2c0743ce34cd0d5055.tar.gz
[SCSI] fix up documentation for change in ->queuecommand to lockless calling
The current doc still says we call it with the host lock held, which is going to cause confusion. Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'Documentation/scsi')
-rw-r--r--Documentation/scsi/scsi_mid_low_api.txt59
1 files changed, 31 insertions, 28 deletions
diff --git a/Documentation/scsi/scsi_mid_low_api.txt b/Documentation/scsi/scsi_mid_low_api.txt
index 570ef2b3d79..df322c10346 100644
--- a/Documentation/scsi/scsi_mid_low_api.txt
+++ b/Documentation/scsi/scsi_mid_low_api.txt
@@ -1044,9 +1044,9 @@ Details:
/**
- * queuecommand - queue scsi command, invoke 'done' on completion
+ * queuecommand - queue scsi command, invoke scp->scsi_done on completion
+ * @shost: pointer to the scsi host object
* @scp: pointer to scsi command object
- * @done: function pointer to be invoked on completion
*
* Returns 0 on success.
*
@@ -1074,42 +1074,45 @@ Details:
*
* Other types of errors that are detected immediately may be
* flagged by setting scp->result to an appropriate value,
- * invoking the 'done' callback, and then returning 0 from this
- * function. If the command is not performed immediately (and the
- * LLD is starting (or will start) the given command) then this
- * function should place 0 in scp->result and return 0.
+ * invoking the scp->scsi_done callback, and then returning 0
+ * from this function. If the command is not performed
+ * immediately (and the LLD is starting (or will start) the given
+ * command) then this function should place 0 in scp->result and
+ * return 0.
*
* Command ownership. If the driver returns zero, it owns the
- * command and must take responsibility for ensuring the 'done'
- * callback is executed. Note: the driver may call done before
- * returning zero, but after it has called done, it may not
- * return any value other than zero. If the driver makes a
- * non-zero return, it must not execute the command's done
- * callback at any time.
- *
- * Locks: struct Scsi_Host::host_lock held on entry (with "irqsave")
- * and is expected to be held on return.
+ * command and must take responsibility for ensuring the
+ * scp->scsi_done callback is executed. Note: the driver may
+ * call scp->scsi_done before returning zero, but after it has
+ * called scp->scsi_done, it may not return any value other than
+ * zero. If the driver makes a non-zero return, it must not
+ * execute the command's scsi_done callback at any time.
+ *
+ * Locks: up to and including 2.6.36, struct Scsi_Host::host_lock
+ * held on entry (with "irqsave") and is expected to be
+ * held on return. From 2.6.37 onwards, queuecommand is
+ * called without any locks held.
*
* Calling context: in interrupt (soft irq) or process context
*
- * Notes: This function should be relatively fast. Normally it will
- * not wait for IO to complete. Hence the 'done' callback is invoked
- * (often directly from an interrupt service routine) some time after
- * this function has returned. In some cases (e.g. pseudo adapter
- * drivers that manufacture the response to a SCSI INQUIRY)
- * the 'done' callback may be invoked before this function returns.
- * If the 'done' callback is not invoked within a certain period
- * the SCSI mid level will commence error processing.
- * If a status of CHECK CONDITION is placed in "result" when the
- * 'done' callback is invoked, then the LLD driver should
- * perform autosense and fill in the struct scsi_cmnd::sense_buffer
+ * Notes: This function should be relatively fast. Normally it
+ * will not wait for IO to complete. Hence the scp->scsi_done
+ * callback is invoked (often directly from an interrupt service
+ * routine) some time after this function has returned. In some
+ * cases (e.g. pseudo adapter drivers that manufacture the
+ * response to a SCSI INQUIRY) the scp->scsi_done callback may be
+ * invoked before this function returns. If the scp->scsi_done
+ * callback is not invoked within a certain period the SCSI mid
+ * level will commence error processing. If a status of CHECK
+ * CONDITION is placed in "result" when the scp->scsi_done
+ * callback is invoked, then the LLD driver should perform
+ * autosense and fill in the struct scsi_cmnd::sense_buffer
* array. The scsi_cmnd::sense_buffer array is zeroed prior to
* the mid level queuing a command to an LLD.
*
* Defined in: LLD
**/
- int queuecommand(struct scsi_cmnd * scp,
- void (*done)(struct scsi_cmnd *))
+ int queuecommand(struct Scsi_Host *shost, struct scsi_cmnd * scp)
/**