From 4344d07fb8dbf0cbfec1f7d7c1afeccaceaaa120 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 19 Apr 2009 08:46:03 +0900 Subject: [PATCH] ide-tape: simplify read/write functions Impact: cleanup idetape_chrdev_read/write() functions are unnecessarily complex when everything can be handled in a single loop. Collapse idetape_add_chrdev_read/write_request() into the rw functions and simplify the implementation. Signed-off-by: Tejun Heo --- drivers/ide/ide-tape.c | 149 ++++++++++++++--------------------------- 1 file changed, 50 insertions(+), 99 deletions(-) diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c index d5e9bb286e30..2599579e4174 100644 --- a/drivers/ide/ide-tape.c +++ b/drivers/ide/ide-tape.c @@ -953,14 +953,6 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd) pc->flags |= PC_FLAG_WAIT_FOR_DSC; } -/* Queue up a character device originated write request. */ -static int idetape_add_chrdev_write_request(ide_drive_t *drive, int size) -{ - debug_log(DBG_CHRDEV, "Enter %s\n", __func__); - - return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, size); -} - static void ide_tape_flush_merge_buffer(ide_drive_t *drive) { idetape_tape_t *tape = drive->driver_data; @@ -974,7 +966,7 @@ static void ide_tape_flush_merge_buffer(ide_drive_t *drive) size_t aligned = roundup(tape->valid, tape->blk_size); memset(tape->cur, 0, aligned - tape->valid); - idetape_add_chrdev_write_request(drive, aligned); + idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, aligned); kfree(tape->buf); tape->buf = NULL; } @@ -1031,20 +1023,6 @@ static int idetape_init_rw(ide_drive_t *drive, int dir) return 0; } -/* called from idetape_chrdev_read() to service a chrdev read request. */ -static int idetape_add_chrdev_read_request(ide_drive_t *drive, int size) -{ - debug_log(DBG_PROCS, "Enter %s, %d bytes\n", __func__, size); - - /* If we are at a filemark, return a read length of 0 */ - if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) - return 0; - - idetape_init_rw(drive, IDETAPE_DIR_READ); - - return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, size); -} - static void idetape_pad_zeros(ide_drive_t *drive, int bcount) { idetape_tape_t *tape = drive->driver_data; @@ -1184,8 +1162,9 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf, { struct ide_tape_obj *tape = file->private_data; ide_drive_t *drive = tape->drive; - ssize_t bytes_read, temp, actually_read = 0, rc; + size_t done = 0; ssize_t ret = 0; + int rc; debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count); @@ -1195,52 +1174,43 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf, (count % tape->blk_size) == 0) tape->user_bs_factor = count / tape->blk_size; } + rc = idetape_init_rw(drive, IDETAPE_DIR_READ); if (rc < 0) return rc; - if (count == 0) - return (0); - if (tape->valid) { - actually_read = min_t(unsigned int, tape->valid, count); - if (copy_to_user(buf, tape->cur, actually_read)) - ret = -EFAULT; - buf += actually_read; - count -= actually_read; - tape->cur += actually_read; - tape->valid -= actually_read; - } - while (count >= tape->buffer_size) { - bytes_read = idetape_add_chrdev_read_request(drive, - tape->buffer_size); - if (bytes_read <= 0) - goto finish; - if (copy_to_user(buf, tape->cur, bytes_read)) - ret = -EFAULT; - buf += bytes_read; - count -= bytes_read; - actually_read += bytes_read; - } - if (count) { - bytes_read = idetape_add_chrdev_read_request(drive, - tape->buffer_size); - if (bytes_read <= 0) - goto finish; - temp = min((unsigned long)count, (unsigned long)bytes_read); - if (copy_to_user(buf, tape->cur, temp)) + + while (done < count) { + size_t todo; + + /* refill if staging buffer is empty */ + if (!tape->valid) { + /* If we are at a filemark, nothing more to read */ + if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) + break; + /* read */ + if (idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, + tape->buffer_size) <= 0) + break; + } + + /* copy out */ + todo = min_t(size_t, count - done, tape->valid); + if (copy_to_user(buf + done, tape->cur, todo)) ret = -EFAULT; - actually_read += temp; - tape->cur += temp; - tape->valid -= temp; + + tape->cur += todo; + tape->valid -= todo; + done += todo; } -finish: - if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) { + + if (!done && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) { debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name); idetape_space_over_filemarks(drive, MTFSF, 1); return 0; } - return ret ? ret : actually_read; + return ret ? ret : done; } static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, @@ -1248,7 +1218,7 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, { struct ide_tape_obj *tape = file->private_data; ide_drive_t *drive = tape->drive; - ssize_t actually_written = 0; + size_t done = 0; ssize_t ret = 0; int rc; @@ -1262,47 +1232,28 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, rc = idetape_init_rw(drive, IDETAPE_DIR_WRITE); if (rc < 0) return rc; - if (count == 0) - return (0); - if (tape->valid < tape->buffer_size) { - actually_written = min_t(unsigned int, - tape->buffer_size - tape->valid, - count); - if (copy_from_user(tape->cur, buf, actually_written)) - ret = -EFAULT; - buf += actually_written; - count -= actually_written; - tape->cur += actually_written; - tape->valid += actually_written; - - if (tape->valid == tape->buffer_size) { - ssize_t retval; - retval = idetape_add_chrdev_write_request(drive, - tape->buffer_size); - if (retval <= 0) - return (retval); - } - } - while (count >= tape->buffer_size) { - ssize_t retval; - if (copy_from_user(tape->cur, buf, tape->buffer_size)) - ret = -EFAULT; - buf += tape->buffer_size; - count -= tape->buffer_size; - retval = idetape_add_chrdev_write_request(drive, - tape->buffer_size); - actually_written += tape->buffer_size; - if (retval <= 0) - return (retval); - } - if (count) { - actually_written += count; - if (copy_from_user(tape->cur, buf, count)) + + while (done < count) { + size_t todo; + + /* flush if staging buffer is full */ + if (tape->valid == tape->buffer_size && + idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, + tape->buffer_size) <= 0) + return rc; + + /* copy in */ + todo = min_t(size_t, count - done, + tape->buffer_size - tape->valid); + if (copy_from_user(tape->cur, buf + done, todo)) ret = -EFAULT; - tape->cur += count; - tape->valid += count; + + tape->cur += todo; + tape->valid += todo; + done += todo; } - return ret ? ret : actually_written; + + return ret ? ret : done; } static int idetape_write_filemark(ide_drive_t *drive) -- 2.20.1