[RFC PATCH 0/3] ide-atapi cleanups

[RFC PATCH 0/3] ide-atapi cleanups

[Borislav Petkov]

Hi Bart, hi Tejun,

here's a small conversion attempt to Tejun's struct request API change.
This is not ripe material yet and has more of a rfc nature so that we
could see more concretely how LLDDs might use and not abuse :) block
layer interfaces.

This is based ontop of

git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc.git block-unify-sector-and-data_len

and has been lightly tested with ide-floppy.

Thanks,
Boris.

[PATCH 1/3] ide-tape: fix potential fs requests bug

[Borislav Petkov]

ide-tape had a potential bug for fs requests when preparing the command
packet: it was writing the transfer length as a number of fixed blocks.
However, the block layer implies 512 byte blocks and ide-tape can have
other block sizes so account for that too.

ide-floppy does this calculation properly with the block size factor
(floppy->bs_factor).

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
---
 drivers/ide/ide-tape.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index e166045..fc79cf4 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -586,7 +586,7 @@ static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
 				   struct ide_atapi_pc *pc, struct request *rq,
 				   u8 opcode)
 {
-	unsigned int length = blk_rq_sectors(rq);
+	unsigned int length = blk_rq_sectors(rq) / (tape->blk_size >> 9);
 
 	ide_init_pc(pc);
 	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
-- 
1.6.2.4

[PATCH 2/3] ide-atapi: switch to blk_rq_bytes() on do_request() path

[Borislav Petkov]

After the recent struct request cleanups, blk_rq_bytes() is guaranteed
to be valid. Use that instead of pc->req_xfer in the do_request() path
after the command has been queued.

The remaining usage of pc->req_xfer now is only until we map the rq to a
bio.

While at it:

- remove local caching of rq completion length in ide_tape_issue_pc()

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
---
 drivers/ide/ide-atapi.c  |   12 +++++++-----
 drivers/ide/ide-floppy.c |    8 ++++----
 drivers/ide/ide-tape.c   |   12 ++++++------
 3 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index 792534d..cacffd4 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -360,7 +360,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 						     ? "write" : "read");
 			pc->flags |= PC_FLAG_DMA_ERROR;
 		} else
-			pc->xferred = pc->req_xfer;
+			pc->xferred = blk_rq_bytes(rq);
 		debug_log("%s: DMA finished\n", drive->name);
 	}
 
@@ -617,7 +617,7 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
 	ide_hwif_t *hwif = drive->hwif;
 	ide_expiry_t *expiry = NULL;
 	struct request *rq = hwif->rq;
-	unsigned int timeout;
+	unsigned int timeout, bytes;
 	u16 bcount;
 	u8 valid_tf;
 	u8 drq_int = !!(drive->atapi_flags & IDE_AFLAG_DRQ_INTERRUPT);
@@ -637,9 +637,11 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
 		pc->xferred = 0;
 
 		valid_tf = IDE_VALID_DEVICE;
-		bcount = ((drive->media == ide_tape) ?
-				pc->req_xfer :
-				min(pc->req_xfer, 63 * 1024));
+		bytes = blk_rq_bytes(rq);
+
+		bcount = ((drive->media == ide_tape) ? bytes
+						     : min_t(unsigned int,
+							     bytes, 63 * 1024));
 
 		if (pc->flags & PC_FLAG_DMA_ERROR) {
 			pc->flags &= ~PC_FLAG_DMA_ERROR;
diff --git a/drivers/ide/ide-floppy.c b/drivers/ide/ide-floppy.c
index 6509817..a1c5598 100644
--- a/drivers/ide/ide-floppy.c
+++ b/drivers/ide/ide-floppy.c
@@ -210,7 +210,7 @@ static void idefloppy_create_rw_cmd(ide_drive_t *drive,
 	if (rq->cmd_flags & REQ_RW)
 		pc->flags |= PC_FLAG_WRITING;
 	pc->buf = NULL;
-	pc->req_xfer = pc->buf_size = blocks * floppy->block_size;
+	pc->buf_size = blk_rq_bytes(rq);
 	pc->flags |= PC_FLAG_DMA_OK;
 }
 
@@ -227,7 +227,7 @@ static void idefloppy_blockpc_cmd(struct ide_disk_obj *floppy,
 	}
 	/* pio will be performed by ide_pio_bytes() which handles sg fine */
 	pc->buf = NULL;
-	pc->req_xfer = pc->buf_size = blk_rq_bytes(rq);
+	pc->buf_size = blk_rq_bytes(rq);
 }
 
 static ide_startstop_t ide_floppy_do_request(ide_drive_t *drive,
@@ -286,8 +286,8 @@ static ide_startstop_t ide_floppy_do_request(ide_drive_t *drive,
 
 	cmd.rq = rq;
 
-	if (blk_fs_request(rq) || pc->req_xfer) {
-		ide_init_sg_cmd(&cmd, pc->req_xfer);
+	if (blk_fs_request(rq) || blk_rq_bytes(rq)) {
+		ide_init_sg_cmd(&cmd, blk_rq_bytes(rq));
 		ide_map_sg(drive, &cmd);
 	}
 
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index fc79cf4..25463c5 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -292,6 +292,7 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 {
 	idetape_tape_t *tape = drive->driver_data;
 	struct ide_atapi_pc *pc = drive->failed_pc;
+	struct request *rq = drive->hwif->rq;
 
 	tape->sense_key = sense[2] & 0xF;
 	tape->asc       = sense[12];
@@ -302,7 +303,7 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 
 	/* Correct pc->xferred by asking the tape.	 */
 	if (pc->flags & PC_FLAG_DMA_ERROR)
-		pc->xferred = pc->req_xfer -
+		pc->xferred = blk_rq_bytes(rq) -
 			tape->blk_size *
 			get_unaligned_be32(&sense[3]);
 
@@ -484,6 +485,7 @@ static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive,
 					 struct ide_atapi_pc *pc)
 {
 	idetape_tape_t *tape = drive->driver_data;
+	struct request *rq = drive->hwif->rq;
 
 	if (drive->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
 		drive->failed_pc = pc;
@@ -493,7 +495,6 @@ static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive,
 
 	if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
 		(pc->flags & PC_FLAG_ABORT)) {
-		unsigned int done = blk_rq_bytes(drive->hwif->rq);
 
 		/*
 		 * We will "abort" retrying a packet command in case legitimate
@@ -517,7 +518,7 @@ static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive,
 
 		drive->failed_pc = NULL;
 		drive->pc_callback(drive, 0);
-		ide_complete_rq(drive, -EIO, done);
+		ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));
 		return ide_stopped;
 	}
 	debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
@@ -592,8 +593,7 @@ static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
 	put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
 	pc->c[1] = 1;
 	pc->buf = NULL;
-	pc->buf_size = length * tape->blk_size;
-	pc->req_xfer = pc->buf_size;
+	pc->buf_size = blk_rq_bytes(rq);
 	if (pc->req_xfer == tape->buffer_size)
 		pc->flags |= PC_FLAG_DMA_OK;
 
@@ -718,7 +718,7 @@ out:
 
 	cmd.rq = rq;
 
-	ide_init_sg_cmd(&cmd, pc->req_xfer);
+	ide_init_sg_cmd(&cmd, blk_rq_bytes(rq));
 	ide_map_sg(drive, &cmd);
 
 	return ide_tape_issue_pc(drive, &cmd, pc);
-- 
1.6.2.4

[PATCH 3/3] ide-atapi: switch to rq->resid_len

[Borislav Petkov]

Now that we have rq->resid_len, use it to account partial completion
amount during the lifetime of an rq, decrementing it on each successful
transfer. As a result, get rid of now unused pc->xferred.

While at it, remove noisy debug call in ide_prep_sense.

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
---
 drivers/ide/ide-atapi.c |   17 ++++++++---------
 drivers/ide/ide-tape.c  |   11 ++++-------
 include/linux/ide.h     |    2 --
 3 files changed, 12 insertions(+), 18 deletions(-)

diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index cacffd4..1f2af8b 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -172,8 +172,6 @@ void ide_prep_sense(ide_drive_t *drive, struct request *rq)
 	unsigned int cmd_len, sense_len;
 	int err;
 
-	debug_log("%s: enter\n", __func__);
-
 	switch (drive->media) {
 	case ide_floppy:
 		cmd_len = 255;
@@ -360,7 +358,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 						     ? "write" : "read");
 			pc->flags |= PC_FLAG_DMA_ERROR;
 		} else
-			pc->xferred = blk_rq_bytes(rq);
+			rq->resid_len = 0;
 		debug_log("%s: DMA finished\n", drive->name);
 	}
 
@@ -369,7 +367,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 		int uptodate, error;
 
 		debug_log("Packet command completed, %d bytes transferred\n",
-			  pc->xferred);
+			  blk_rq_bytes(rq));
 
 		pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
 
@@ -457,15 +455,15 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 	ide_pio_bytes(drive, cmd, write, done);
 
 	/* Update transferred byte count */
-	pc->xferred += done;
+	rq->resid_len -= done;
 
 	bcount -= done;
 
 	if (bcount)
 		ide_pad_transfer(drive, write, bcount);
 
-	debug_log("[cmd %x] transferred %d bytes, padded %d bytes\n",
-		  rq->cmd[0], done, bcount);
+	debug_log("[cmd %x] transferred %d bytes, padded %d bytes, resid: %u\n",
+		  rq->cmd[0], done, bcount, rq->resid_len);
 
 	/* And set the interrupt handler again */
 	ide_set_handler(drive, ide_pc_intr, timeout);
@@ -633,8 +631,6 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
 	} else {
 		pc = drive->pc;
 
-		/* We haven't transferred any data yet */
-		pc->xferred = 0;
 
 		valid_tf = IDE_VALID_DEVICE;
 		bytes = blk_rq_bytes(rq);
@@ -643,6 +639,9 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
 						     : min_t(unsigned int,
 							     bytes, 63 * 1024));
 
+		/* We haven't transferred any data yet */
+		rq->resid_len = bcount;
+
 		if (pc->flags & PC_FLAG_DMA_ERROR) {
 			pc->flags &= ~PC_FLAG_DMA_ERROR;
 			ide_dma_off(drive);
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 25463c5..35c188a 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -301,11 +301,9 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 	debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
 		 pc->c[0], tape->sense_key, tape->asc, tape->ascq);
 
-	/* Correct pc->xferred by asking the tape.	 */
+	/* correct remaining bytes to transfer */
 	if (pc->flags & PC_FLAG_DMA_ERROR)
-		pc->xferred = blk_rq_bytes(rq) -
-			tape->blk_size *
-			get_unaligned_be32(&sense[3]);
+		rq->resid_len = tape->blk_size * get_unaligned_be32(&sense[3]);
 
 	/*
 	 * If error was the result of a zero-length read or write command,
@@ -339,7 +337,7 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 			pc->flags |= PC_FLAG_ABORT;
 		}
 		if (!(pc->flags & PC_FLAG_ABORT) &&
-		    pc->xferred)
+		    (blk_rq_bytes(rq) - rq->resid_len))
 			pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
 	}
 }
@@ -369,7 +367,7 @@ static int ide_tape_callback(ide_drive_t *drive, int dsc)
 			printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
 					"itself - Aborting request!\n");
 	} else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
-		int blocks = pc->xferred / tape->blk_size;
+		int blocks = (blk_rq_bytes(rq) - rq->resid_len) / tape->blk_size;
 
 		tape->avg_size += blocks * tape->blk_size;
 
@@ -381,7 +379,6 @@ static int ide_tape_callback(ide_drive_t *drive, int dsc)
 		}
 
 		tape->first_frame += blocks;
-		rq->resid_len = blk_rq_bytes(rq) - blocks * tape->blk_size;
 
 		if (pc->error) {
 			uptodate = 0;
diff --git a/include/linux/ide.h b/include/linux/ide.h
index 34c128f..745a393 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -357,8 +357,6 @@ struct ide_atapi_pc {
 
 	/* bytes to transfer */
 	int req_xfer;
-	/* bytes actually transferred */
-	int xferred;
 
 	/* data buffer */
 	u8 *buf;
-- 
1.6.2.4