From 03aba2f79594ca94d159c8bab454de9bcc385b76 Mon Sep 17 00:00:00 2001 From: Luben Tuikov Date: Fri, 23 Jun 2006 09:39:09 -0700 Subject: [SCSI] sd/scsi_lib simplify sd_rw_intr and scsi_io_completion This patch simplifies "good_bytes" computation in sd_rw_intr(). sd: "good_bytes" computation is always done in terms of the resolution of the device's medium, since after that it is the number of good bytes we pass around and other layers/contexts (as opposed ot sd) can translate that to their own resolution (block layer:512). It also makes scsi_io_completion() processing more straightforward, eliminating the 3rd argument to the function. It also fixes a couple of bugs like not checking return value, using "break" instead of "return;", etc. I've been running with this patch for some time now on a test (do-it-all) system. Signed-off-by: Luben Tuikov Signed-off-by: James Bottomley --- drivers/scsi/scsi_lib.c | 108 +++++++++++++++++++----------------------------- 1 file changed, 42 insertions(+), 66 deletions(-) (limited to 'drivers/scsi/scsi_lib.c') diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 3d04a9f386a..4c4add53d69 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -855,8 +855,7 @@ static void scsi_release_buffers(struct scsi_cmnd *cmd) * b) We can just use scsi_requeue_command() here. This would * be used if we just wanted to retry, for example. */ -void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, - unsigned int block_bytes) +void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) { int result = cmd->result; int this_count = cmd->bufflen; @@ -921,87 +920,72 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, * Next deal with any sectors which we were able to correctly * handle. */ - if (good_bytes >= 0) { - SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n", + if (good_bytes > 0) { + SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, " + "%d bytes done.\n", req->nr_sectors, good_bytes)); SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); if (clear_errors) req->errors = 0; - /* - * If multiple sectors are requested in one buffer, then - * they will have been finished off by the first command. - * If not, then we have a multi-buffer command. - * - * If block_bytes != 0, it means we had a medium error - * of some sort, and that we want to mark some number of - * sectors as not uptodate. Thus we want to inhibit - * requeueing right here - we will requeue down below - * when we handle the bad sectors. - */ - /* - * If the command completed without error, then either - * finish off the rest of the command, or start a new one. + /* A number of bytes were successfully read. If there + * is leftovers and there is some kind of error + * (result != 0), retry the rest. */ - if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL) + if (scsi_end_request(cmd, 1, good_bytes, !!result) == NULL) return; } - /* - * Now, if we were good little boys and girls, Santa left us a request - * sense buffer. We can extract information from this, so we - * can choose a block to remap, etc. + + /* good_bytes = 0, or (inclusive) there were leftovers and + * result = 0, so scsi_end_request couldn't retry. */ if (sense_valid && !sense_deferred) { switch (sshdr.sense_key) { case UNIT_ATTENTION: if (cmd->device->removable) { - /* detected disc change. set a bit + /* Detected disc change. Set a bit * and quietly refuse further access. */ cmd->device->changed = 1; - scsi_end_request(cmd, 0, - this_count, 1); + scsi_end_request(cmd, 0, this_count, 1); return; } else { - /* - * Must have been a power glitch, or a - * bus reset. Could not have been a - * media change, so we just retry the - * request and see what happens. - */ + /* Must have been a power glitch, or a + * bus reset. Could not have been a + * media change, so we just retry the + * request and see what happens. + */ scsi_requeue_command(q, cmd); return; } break; case ILLEGAL_REQUEST: - /* - * If we had an ILLEGAL REQUEST returned, then we may - * have performed an unsupported command. The only - * thing this should be would be a ten byte read where - * only a six byte read was supported. Also, on a - * system where READ CAPACITY failed, we may have read - * past the end of the disk. - */ + /* If we had an ILLEGAL REQUEST returned, then + * we may have performed an unsupported + * command. The only thing this should be + * would be a ten byte read where only a six + * byte read was supported. Also, on a system + * where READ CAPACITY failed, we may have + * read past the end of the disk. + */ if ((cmd->device->use_10_for_rw && sshdr.asc == 0x20 && sshdr.ascq == 0x00) && (cmd->cmnd[0] == READ_10 || cmd->cmnd[0] == WRITE_10)) { cmd->device->use_10_for_rw = 0; - /* - * This will cause a retry with a 6-byte - * command. + /* This will cause a retry with a + * 6-byte command. */ scsi_requeue_command(q, cmd); - result = 0; + return; } else { scsi_end_request(cmd, 0, this_count, 1); return; } break; case NOT_READY: - /* - * If the device is in the process of becoming + /* If the device is in the process of becoming * ready, or has a temporary blockage, retry. */ if (sshdr.asc == 0x04) { @@ -1021,7 +1005,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, } if (!(req->flags & REQ_QUIET)) { scmd_printk(KERN_INFO, cmd, - "Device not ready: "); + "Device not ready: "); scsi_print_sense_hdr("", &sshdr); } scsi_end_request(cmd, 0, this_count, 1); @@ -1029,21 +1013,21 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, case VOLUME_OVERFLOW: if (!(req->flags & REQ_QUIET)) { scmd_printk(KERN_INFO, cmd, - "Volume overflow, CDB: "); + "Volume overflow, CDB: "); __scsi_print_command(cmd->data_cmnd); scsi_print_sense("", cmd); } - scsi_end_request(cmd, 0, block_bytes, 1); + /* See SSC3rXX or current. */ + scsi_end_request(cmd, 0, this_count, 1); return; default: break; } - } /* driver byte != 0 */ + } if (host_byte(result) == DID_RESET) { - /* - * Third party bus reset or reset for error - * recovery reasons. Just retry the request - * and see what happens. + /* Third party bus reset or reset for error recovery + * reasons. Just retry the request and see what + * happens. */ scsi_requeue_command(q, cmd); return; @@ -1051,21 +1035,13 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, if (result) { if (!(req->flags & REQ_QUIET)) { scmd_printk(KERN_INFO, cmd, - "SCSI error: return code = 0x%x\n", result); - + "SCSI error: return code = 0x%08x\n", + result); if (driver_byte(result) & DRIVER_SENSE) scsi_print_sense("", cmd); } - /* - * Mark a single buffer as not uptodate. Queue the remainder. - * We sometimes get this cruft in the event that a medium error - * isn't properly reported. - */ - block_bytes = req->hard_cur_sectors << 9; - if (!block_bytes) - block_bytes = req->data_len; - scsi_end_request(cmd, 0, block_bytes, 1); } + scsi_end_request(cmd, 0, this_count, !result); } EXPORT_SYMBOL(scsi_io_completion); @@ -1169,7 +1145,7 @@ static void scsi_blk_pc_done(struct scsi_cmnd *cmd) * successfully. Since this is a REQ_BLOCK_PC command the * caller should check the request's errors value */ - scsi_io_completion(cmd, cmd->bufflen, 0); + scsi_io_completion(cmd, cmd->bufflen); } static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd) -- cgit v1.2.3