From 30b0c37b27485a9cb897bfe3824f6f517b8c80d6 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Thu, 13 Dec 2007 13:47:40 +0200 Subject: [SCSI] implement scsi_data_buffer In preparation for bidi we abstract all IO members of scsi_cmnd, that will need to duplicate, into a substructure. - Group all IO members of scsi_cmnd into a scsi_data_buffer structure. - Adjust accessors to new members. - scsi_{alloc,free}_sgtable receive a scsi_data_buffer instead of scsi_cmnd. And work on it. - Adjust scsi_init_io() and scsi_release_buffers() for above change. - Fix other parts of scsi_lib/scsi.c to members migration. Use accessors where appropriate. - fix Documentation about scsi_cmnd in scsi_host.h - scsi_error.c * Changed needed members of struct scsi_eh_save. * Careful considerations in scsi_eh_prep/restore_cmnd. - sd.c and sr.c * sd and sr would adjust IO size to align on device's block size so code needs to change once we move to scsi_data_buff implementation. * Convert code to use scsi_for_each_sg * Use data accessors where appropriate. - tgt: convert libsrp to use scsi_data_buffer - isd200: This driver still bangs on scsi_cmnd IO members, so need changing [jejb: rebased on top of sg_table patches fixed up conflicts and used the synergy to eliminate use_sg and sg_count] Signed-off-by: Boaz Harrosh Signed-off-by: FUJITA Tomonori Signed-off-by: James Bottomley --- drivers/scsi/scsi_lib.c | 63 ++++++++++++++++++++----------------------------- 1 file changed, 25 insertions(+), 38 deletions(-) (limited to 'drivers/scsi/scsi_lib.c') diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 69fd62183ba..d5e77e9b3a9 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -440,7 +440,7 @@ EXPORT_SYMBOL_GPL(scsi_execute_async); static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) { cmd->serial_number = 0; - cmd->resid = 0; + scsi_set_resid(cmd, 0); memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); if (cmd->cmd_len == 0) cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); @@ -746,25 +746,25 @@ static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) return mempool_alloc(sgp->pool, gfp_mask); } -static int scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask) +static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, + gfp_t gfp_mask) { int ret; - BUG_ON(!cmd->use_sg); + BUG_ON(!nents); - ret = __sg_alloc_table(&cmd->sg_table, cmd->use_sg, - SCSI_MAX_SG_SEGMENTS, gfp_mask, scsi_sg_alloc); + ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, + gfp_mask, scsi_sg_alloc); if (unlikely(ret)) - __sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS, + __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); - cmd->request_buffer = cmd->sg_table.sgl; return ret; } -static void scsi_free_sgtable(struct scsi_cmnd *cmd) +static void scsi_free_sgtable(struct scsi_data_buffer *sdb) { - __sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); + __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); } /* @@ -786,15 +786,10 @@ static void scsi_free_sgtable(struct scsi_cmnd *cmd) */ void scsi_release_buffers(struct scsi_cmnd *cmd) { - if (cmd->use_sg) - scsi_free_sgtable(cmd); + if (cmd->sdb.table.nents) + scsi_free_sgtable(&cmd->sdb); - /* - * Zero these out. They now point to freed memory, and it is - * dangerous to hang onto the pointers. - */ - cmd->request_buffer = NULL; - cmd->request_bufflen = 0; + memset(&cmd->sdb, 0, sizeof(cmd->sdb)); } EXPORT_SYMBOL(scsi_release_buffers); @@ -829,7 +824,7 @@ EXPORT_SYMBOL(scsi_release_buffers); void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) { int result = cmd->result; - int this_count = cmd->request_bufflen; + int this_count = scsi_bufflen(cmd); struct request_queue *q = cmd->device->request_queue; struct request *req = cmd->request; int clear_errors = 1; @@ -837,8 +832,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) int sense_valid = 0; int sense_deferred = 0; - scsi_release_buffers(cmd); - if (result) { sense_valid = scsi_command_normalize_sense(cmd, &sshdr); if (sense_valid) @@ -861,9 +854,11 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) req->sense_len = len; } } - req->data_len = cmd->resid; + req->data_len = scsi_get_resid(cmd); } + scsi_release_buffers(cmd); + /* * Next deal with any sectors which we were able to correctly * handle. @@ -871,7 +866,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 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; @@ -1002,35 +996,30 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) { struct request *req = cmd->request; int count; - - /* - * We used to not use scatter-gather for single segment request, - * but now we do (it makes highmem I/O easier to support without - * kmapping pages) - */ - cmd->use_sg = req->nr_phys_segments; + struct scsi_data_buffer *sdb = &cmd->sdb; /* * If sg table allocation fails, requeue request later. */ - if (unlikely(scsi_alloc_sgtable(cmd, gfp_mask))) { + if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, + gfp_mask))) { scsi_unprep_request(req); return BLKPREP_DEFER; } req->buffer = NULL; if (blk_pc_request(req)) - cmd->request_bufflen = req->data_len; + sdb->length = req->data_len; else - cmd->request_bufflen = req->nr_sectors << 9; + sdb->length = req->nr_sectors << 9; /* * Next, walk the list, and fill in the addresses and sizes of * each segment. */ - count = blk_rq_map_sg(req->q, req, cmd->request_buffer); - BUG_ON(count > cmd->use_sg); - cmd->use_sg = count; + count = blk_rq_map_sg(req->q, req, sdb->table.sgl); + BUG_ON(count > sdb->table.nents); + sdb->table.nents = count; return BLKPREP_OK; } EXPORT_SYMBOL(scsi_init_io); @@ -1086,9 +1075,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) BUG_ON(req->data_len); BUG_ON(req->data); - cmd->request_bufflen = 0; - cmd->request_buffer = NULL; - cmd->use_sg = 0; + memset(&cmd->sdb, 0, sizeof(cmd->sdb)); req->buffer = NULL; } -- cgit v1.2.3