diff options
author | James Bottomley <James.Bottomley@suse.de> | 2010-12-16 09:22:24 -0500 |
---|---|---|
committer | James Bottomley <James.Bottomley@suse.de> | 2010-12-21 09:23:54 -0500 |
commit | 29687512c0b084957112cc2c0743ce34cd0d5055 (patch) | |
tree | dc44aff0b61e8bed3ea664c5a872d04bad8c4132 /Documentation/scsi/scsi_mid_low_api.txt | |
parent | 8816624222b12e5d7e291e9d1973fc42b994eb6b (diff) |
[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/scsi_mid_low_api.txt')
-rw-r--r-- | Documentation/scsi/scsi_mid_low_api.txt | 59 |
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 570ef2b3d79b..df322c103466 100644 --- a/Documentation/scsi/scsi_mid_low_api.txt +++ b/Documentation/scsi/scsi_mid_low_api.txt | |||
@@ -1044,9 +1044,9 @@ Details: | |||
1044 | 1044 | ||
1045 | 1045 | ||
1046 | /** | 1046 | /** |
1047 | * queuecommand - queue scsi command, invoke 'done' on completion | 1047 | * queuecommand - queue scsi command, invoke scp->scsi_done on completion |
1048 | * @shost: pointer to the scsi host object | ||
1048 | * @scp: pointer to scsi command object | 1049 | * @scp: pointer to scsi command object |
1049 | * @done: function pointer to be invoked on completion | ||
1050 | * | 1050 | * |
1051 | * Returns 0 on success. | 1051 | * Returns 0 on success. |
1052 | * | 1052 | * |
@@ -1074,42 +1074,45 @@ Details: | |||
1074 | * | 1074 | * |
1075 | * Other types of errors that are detected immediately may be | 1075 | * Other types of errors that are detected immediately may be |
1076 | * flagged by setting scp->result to an appropriate value, | 1076 | * flagged by setting scp->result to an appropriate value, |
1077 | * invoking the 'done' callback, and then returning 0 from this | 1077 | * invoking the scp->scsi_done callback, and then returning 0 |
1078 | * function. If the command is not performed immediately (and the | 1078 | * from this function. If the command is not performed |
1079 | * LLD is starting (or will start) the given command) then this | 1079 | * immediately (and the LLD is starting (or will start) the given |
1080 | * function should place 0 in scp->result and return 0. | 1080 | * command) then this function should place 0 in scp->result and |
1081 | * return 0. | ||
1081 | * | 1082 | * |
1082 | * Command ownership. If the driver returns zero, it owns the | 1083 | * Command ownership. If the driver returns zero, it owns the |
1083 | * command and must take responsibility for ensuring the 'done' | 1084 | * command and must take responsibility for ensuring the |
1084 | * callback is executed. Note: the driver may call done before | 1085 | * scp->scsi_done callback is executed. Note: the driver may |
1085 | * returning zero, but after it has called done, it may not | 1086 | * call scp->scsi_done before returning zero, but after it has |
1086 | * return any value other than zero. If the driver makes a | 1087 | * called scp->scsi_done, it may not return any value other than |
1087 | * non-zero return, it must not execute the command's done | 1088 | * zero. If the driver makes a non-zero return, it must not |
1088 | * callback at any time. | 1089 | * execute the command's scsi_done callback at any time. |
1089 | * | 1090 | * |
1090 | * Locks: struct Scsi_Host::host_lock held on entry (with "irqsave") | 1091 | * Locks: up to and including 2.6.36, struct Scsi_Host::host_lock |
1091 | * and is expected to be held on return. | 1092 | * held on entry (with "irqsave") and is expected to be |
1093 | * held on return. From 2.6.37 onwards, queuecommand is | ||
1094 | * called without any locks held. | ||
1092 | * | 1095 | * |
1093 | * Calling context: in interrupt (soft irq) or process context | 1096 | * Calling context: in interrupt (soft irq) or process context |
1094 | * | 1097 | * |
1095 | * Notes: This function should be relatively fast. Normally it will | 1098 | * Notes: This function should be relatively fast. Normally it |
1096 | * not wait for IO to complete. Hence the 'done' callback is invoked | 1099 | * will not wait for IO to complete. Hence the scp->scsi_done |
1097 | * (often directly from an interrupt service routine) some time after | 1100 | * callback is invoked (often directly from an interrupt service |
1098 | * this function has returned. In some cases (e.g. pseudo adapter | 1101 | * routine) some time after this function has returned. In some |
1099 | * drivers that manufacture the response to a SCSI INQUIRY) | 1102 | * cases (e.g. pseudo adapter drivers that manufacture the |
1100 | * the 'done' callback may be invoked before this function returns. | 1103 | * response to a SCSI INQUIRY) the scp->scsi_done callback may be |
1101 | * If the 'done' callback is not invoked within a certain period | 1104 | * invoked before this function returns. If the scp->scsi_done |
1102 | * the SCSI mid level will commence error processing. | 1105 | * callback is not invoked within a certain period the SCSI mid |
1103 | * If a status of CHECK CONDITION is placed in "result" when the | 1106 | * level will commence error processing. If a status of CHECK |
1104 | * 'done' callback is invoked, then the LLD driver should | 1107 | * CONDITION is placed in "result" when the scp->scsi_done |
1105 | * perform autosense and fill in the struct scsi_cmnd::sense_buffer | 1108 | * callback is invoked, then the LLD driver should perform |
1109 | * autosense and fill in the struct scsi_cmnd::sense_buffer | ||
1106 | * array. The scsi_cmnd::sense_buffer array is zeroed prior to | 1110 | * array. The scsi_cmnd::sense_buffer array is zeroed prior to |
1107 | * the mid level queuing a command to an LLD. | 1111 | * the mid level queuing a command to an LLD. |
1108 | * | 1112 | * |
1109 | * Defined in: LLD | 1113 | * Defined in: LLD |
1110 | **/ | 1114 | **/ |
1111 | int queuecommand(struct scsi_cmnd * scp, | 1115 | int queuecommand(struct Scsi_Host *shost, struct scsi_cmnd * scp) |
1112 | void (*done)(struct scsi_cmnd *)) | ||
1113 | 1116 | ||
1114 | 1117 | ||
1115 | /** | 1118 | /** |