From 963da55c4b9eeeb2085ca74ba927cf77bce966d4 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 19 Apr 2009 08:46:02 +0900 Subject: [PATCH] ide-tape: kill idetape_bh Impact: kill now unnecessary idetape_bh With everything using standard mechanisms, there is no need for idetape_bh anymore. Kill it and use tape->buf, cur and valid to describe data buffer instead. Changes worth mentioning are... * idetape_queue_rq_tail() now always queue tape->buf and and adjusts buffer state properly before completion. * idetape_pad_zeros() clears the buffer only once. Signed-off-by: Tejun Heo --- drivers/ide/ide-tape.c | 305 ++++++++++++++----------------------------------- 1 file changed, 84 insertions(+), 221 deletions(-) diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c index b373ac87635..d2e9c09b521 100644 --- a/drivers/ide/ide-tape.c +++ b/drivers/ide/ide-tape.c @@ -131,12 +131,6 @@ enum { IDETAPE_DIR_WRITE = (1 << 2), }; -struct idetape_bh { - u32 b_size; - atomic_t b_count; - char *b_data; -}; - /* Tape door status */ #define DOOR_UNLOCKED 0 #define DOOR_LOCKED 1 @@ -218,14 +212,12 @@ typedef struct ide_tape_obj { /* Data buffer size chosen based on the tape's recommendation */ int buffer_size; - /* merge buffer */ - struct idetape_bh *merge_bh; - /* size of the merge buffer */ - int merge_bh_size; - /* pointer to current buffer head within the merge buffer */ - struct idetape_bh *bh; - char *b_data; - int b_count; + /* Staging buffer of buffer_size bytes */ + void *buf; + /* The read/write cursor */ + void *cur; + /* The number of valid bytes in buf */ + size_t valid; /* Measures average tape speed */ unsigned long avg_time; @@ -351,15 +343,6 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense) } } -/* Free data buffers completely. */ -static void ide_tape_kfree_buffer(idetape_tape_t *tape) -{ - struct idetape_bh *bh = tape->merge_bh; - - kfree(bh->b_data); - kfree(bh); -} - static void ide_tape_handle_dsc(ide_drive_t *); static int ide_tape_callback(ide_drive_t *drive, int dsc) @@ -603,8 +586,7 @@ static void ide_tape_create_rw_cmd(idetape_tape_t *tape, struct ide_atapi_pc *pc, struct request *rq, u8 opcode) { - struct idetape_bh *bh = (struct idetape_bh *)rq->special; - unsigned int length = rq->current_nr_sectors; + unsigned int length = rq->nr_sectors; ide_init_pc(pc); put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]); @@ -616,14 +598,11 @@ static void ide_tape_create_rw_cmd(idetape_tape_t *tape, if (pc->req_xfer == tape->buffer_size) pc->flags |= PC_FLAG_DMA_OK; - if (opcode == READ_6) { + if (opcode == READ_6) pc->c[0] = READ_6; - atomic_set(&bh->b_count, 0); - } else if (opcode == WRITE_6) { + else if (opcode == WRITE_6) { pc->c[0] = WRITE_6; pc->flags |= PC_FLAG_WRITING; - pc->b_data = bh->b_data; - pc->b_count = atomic_read(&bh->b_count); } memcpy(rq->cmd, pc->c, 12); @@ -639,10 +618,8 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive, struct ide_cmd cmd; u8 stat; - debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu," - " current_nr_sectors: %u\n", - (unsigned long long)rq->sector, rq->nr_sectors, - rq->current_nr_sectors); + debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu\n" + (unsigned long long)rq->sector, rq->nr_sectors); if (!(blk_special_request(rq) || blk_sense_request(rq))) { /* We do not support buffer cache originated requests. */ @@ -749,89 +726,6 @@ out: } /* - * It returns a pointer to the newly allocated buffer, or NULL in case - * of failure. - */ -static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape, - int full) -{ - struct idetape_bh *bh; - - bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL); - if (!bh) - return NULL; - - bh->b_data = kmalloc(tape->buffer_size, GFP_KERNEL); - if (!bh->b_data) { - kfree(bh); - return NULL; - } - - bh->b_size = tape->buffer_size; - atomic_set(&bh->b_count, full ? bh->b_size : 0); - - return bh; -} - -static int idetape_copy_stage_from_user(idetape_tape_t *tape, - const char __user *buf, int n) -{ - struct idetape_bh *bh = tape->bh; - int ret = 0; - - if (n) { - if (bh == NULL || n > bh->b_size - atomic_read(&bh->b_count)) { - printk(KERN_ERR "ide-tape: bh == NULL in %s\n", - __func__); - return 1; - } - if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf, - n)) - ret = 1; - atomic_add(n, &bh->b_count); - if (atomic_read(&bh->b_count) == bh->b_size) - tape->bh = NULL; - } - - return ret; -} - -static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf, - int n) -{ - struct idetape_bh *bh = tape->bh; - int ret = 0; - - if (n) { - if (bh == NULL || n > tape->b_count) { - printk(KERN_ERR "ide-tape: bh == NULL in %s\n", - __func__); - return 1; - } - if (copy_to_user(buf, tape->b_data, n)) - ret = 1; - tape->b_data += n; - tape->b_count -= n; - if (!tape->b_count) - tape->bh = NULL; - } - return ret; -} - -static void idetape_init_merge_buffer(idetape_tape_t *tape) -{ - struct idetape_bh *bh = tape->merge_bh; - tape->bh = tape->merge_bh; - - if (tape->chrdev_dir == IDETAPE_DIR_WRITE) - atomic_set(&bh->b_count, 0); - else { - tape->b_data = bh->b_data; - tape->b_count = atomic_read(&bh->b_count); - } -} - -/* * Write a filemark if write_filemark=1. Flush the device buffers without * writing a filemark otherwise. */ @@ -928,10 +822,10 @@ static void __ide_tape_discard_merge_buffer(ide_drive_t *drive) return; clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags); - tape->merge_bh_size = 0; - if (tape->merge_bh != NULL) { - ide_tape_kfree_buffer(tape); - tape->merge_bh = NULL; + tape->valid = 0; + if (tape->buf != NULL) { + kfree(tape->buf); + tape->buf = NULL; } tape->chrdev_dir = IDETAPE_DIR_NONE; @@ -985,8 +879,7 @@ static void ide_tape_discard_merge_buffer(ide_drive_t *drive, * Generate a read/write request for the block device interface and wait for it * to be serviced. */ -static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, - struct idetape_bh *bh) +static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks) { idetape_tape_t *tape = drive->driver_data; size_t size = blocks * tape->blk_size; @@ -1000,11 +893,10 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, rq->cmd_type = REQ_TYPE_SPECIAL; rq->cmd[13] = cmd; rq->rq_disk = tape->disk; - rq->special = (void *)bh; rq->sector = tape->first_frame; if (size) { - ret = blk_rq_map_kern(drive->queue, rq, bh->b_data, size, + ret = blk_rq_map_kern(drive->queue, rq, tape->buf, size, __GFP_WAIT); if (ret) goto out_put; @@ -1012,17 +904,17 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, blk_execute_rq(drive->queue, tape->disk, rq, 0); - /* calculate the number of transferred bytes and update bh */ + /* calculate the number of transferred bytes and update buffer state */ size -= rq->data_len; + tape->cur = tape->buf; if (cmd == REQ_IDETAPE_READ) - atomic_add(size, &bh->b_count); + tape->valid = size; + else + tape->valid = 0; ret = size; if (rq->errors == IDE_DRV_ERROR_GENERAL) ret = -EIO; - - if (tape->merge_bh) - idetape_init_merge_buffer(tape); out_put: blk_put_request(rq); return ret; @@ -1064,49 +956,33 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd) /* Queue up a character device originated write request. */ static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks) { - idetape_tape_t *tape = drive->driver_data; - debug_log(DBG_CHRDEV, "Enter %s\n", __func__); - return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, - blocks, tape->merge_bh); + return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks); } static void ide_tape_flush_merge_buffer(ide_drive_t *drive) { idetape_tape_t *tape = drive->driver_data; int blocks; - struct idetape_bh *bh; if (tape->chrdev_dir != IDETAPE_DIR_WRITE) { printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer" " but we are not writing.\n"); return; } - if (tape->merge_bh_size > tape->buffer_size) { - printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n"); - tape->merge_bh_size = tape->buffer_size; - } - if (tape->merge_bh_size) { - blocks = tape->merge_bh_size / tape->blk_size; - if (tape->merge_bh_size % tape->blk_size) { - unsigned int i = tape->blk_size - - tape->merge_bh_size % tape->blk_size; + if (tape->buf) { + blocks = tape->valid / tape->blk_size; + if (tape->valid % tape->blk_size) { blocks++; - bh = tape->bh; - if (bh) { - memset(bh->b_data + atomic_read(&bh->b_count), - 0, i); - atomic_add(i, &bh->b_count); - } else - printk(KERN_INFO "ide-tape: bug, bh NULL\n"); + memset(tape->buf + tape->valid, 0, + tape->blk_size - tape->valid % tape->blk_size); } (void) idetape_add_chrdev_write_request(drive, blocks); - tape->merge_bh_size = 0; } - if (tape->merge_bh != NULL) { - ide_tape_kfree_buffer(tape); - tape->merge_bh = NULL; + if (tape->buf != NULL) { + kfree(tape->buf); + tape->buf = NULL; } tape->chrdev_dir = IDETAPE_DIR_NONE; } @@ -1122,15 +998,15 @@ static int idetape_init_read(ide_drive_t *drive) ide_tape_flush_merge_buffer(drive); idetape_flush_tape_buffers(drive); } - if (tape->merge_bh || tape->merge_bh_size) { - printk(KERN_ERR "ide-tape: merge_bh_size should be" - " 0 now\n"); - tape->merge_bh_size = 0; + if (tape->buf || tape->valid) { + printk(KERN_ERR "ide-tape: valid should be 0 now\n"); + tape->valid = 0; } - tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0); - if (!tape->merge_bh) + tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL); + if (!tape->buf) return -ENOMEM; tape->chrdev_dir = IDETAPE_DIR_READ; + tape->cur = tape->buf; /* * Issue a read 0 command to ensure that DSC handshake is @@ -1140,11 +1016,10 @@ static int idetape_init_read(ide_drive_t *drive) */ if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) { bytes_read = idetape_queue_rw_tail(drive, - REQ_IDETAPE_READ, 0, - tape->merge_bh); + REQ_IDETAPE_READ, 0); if (bytes_read < 0) { - ide_tape_kfree_buffer(tape); - tape->merge_bh = NULL; + kfree(tape->buf); + tape->buf = NULL; tape->chrdev_dir = IDETAPE_DIR_NONE; return bytes_read; } @@ -1157,8 +1032,6 @@ static int idetape_init_read(ide_drive_t *drive) /* called from idetape_chrdev_read() to service a chrdev read request. */ static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks) { - idetape_tape_t *tape = drive->driver_data; - debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks); /* If we are at a filemark, return a read length of 0 */ @@ -1167,27 +1040,21 @@ static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks) idetape_init_read(drive); - return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, - tape->merge_bh); + return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks); } static void idetape_pad_zeros(ide_drive_t *drive, int bcount) { idetape_tape_t *tape = drive->driver_data; - struct idetape_bh *bh = tape->merge_bh; - int blocks; + + memset(tape->buf, 0, tape->buffer_size); while (bcount) { - unsigned int count; + unsigned int count = min(tape->buffer_size, bcount); - count = min(tape->buffer_size, bcount); + idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, + count / tape->blk_size); bcount -= count; - blocks = count / tape->blk_size; - atomic_set(&bh->b_count, count); - memset(bh->b_data, 0, atomic_read(&bh->b_count)); - - idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, - tape->merge_bh); } } @@ -1267,7 +1134,7 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op, } if (tape->chrdev_dir == IDETAPE_DIR_READ) { - tape->merge_bh_size = 0; + tape->valid = 0; if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) ++count; ide_tape_discard_merge_buffer(drive, 0); @@ -1333,20 +1200,20 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf, return rc; if (count == 0) return (0); - if (tape->merge_bh_size) { - actually_read = min((unsigned int)(tape->merge_bh_size), - (unsigned int)count); - if (idetape_copy_stage_to_user(tape, buf, actually_read)) + 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; - tape->merge_bh_size -= 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, ctl); if (bytes_read <= 0) goto finish; - if (idetape_copy_stage_to_user(tape, buf, bytes_read)) + if (copy_to_user(buf, tape->cur, bytes_read)) ret = -EFAULT; buf += bytes_read; count -= bytes_read; @@ -1357,10 +1224,11 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf, if (bytes_read <= 0) goto finish; temp = min((unsigned long)count, (unsigned long)bytes_read); - if (idetape_copy_stage_to_user(tape, buf, temp)) + if (copy_to_user(buf, tape->cur, temp)) ret = -EFAULT; actually_read += temp; - tape->merge_bh_size = bytes_read-temp; + tape->cur += temp; + tape->valid -= temp; } finish: if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) { @@ -1392,16 +1260,15 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, if (tape->chrdev_dir != IDETAPE_DIR_WRITE) { if (tape->chrdev_dir == IDETAPE_DIR_READ) ide_tape_discard_merge_buffer(drive, 1); - if (tape->merge_bh || tape->merge_bh_size) { - printk(KERN_ERR "ide-tape: merge_bh_size " - "should be 0 now\n"); - tape->merge_bh_size = 0; + if (tape->buf || tape->valid) { + printk(KERN_ERR "ide-tape: valid should be 0 now\n"); + tape->valid = 0; } - tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0); - if (!tape->merge_bh) + tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL); + if (!tape->buf) return -ENOMEM; tape->chrdev_dir = IDETAPE_DIR_WRITE; - idetape_init_merge_buffer(tape); + tape->cur = tape->buf; /* * Issue a write 0 command to ensure that DSC handshake is @@ -1411,11 +1278,10 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, */ if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) { ssize_t retval = idetape_queue_rw_tail(drive, - REQ_IDETAPE_WRITE, 0, - tape->merge_bh); + REQ_IDETAPE_WRITE, 0); if (retval < 0) { - ide_tape_kfree_buffer(tape); - tape->merge_bh = NULL; + kfree(tape->buf); + tape->buf = NULL; tape->chrdev_dir = IDETAPE_DIR_NONE; return retval; } @@ -1423,23 +1289,19 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, } if (count == 0) return (0); - if (tape->merge_bh_size) { - if (tape->merge_bh_size >= tape->buffer_size) { - printk(KERN_ERR "ide-tape: bug: merge buf too big\n"); - tape->merge_bh_size = 0; - } - actually_written = min((unsigned int) - (tape->buffer_size - tape->merge_bh_size), - (unsigned int)count); - if (idetape_copy_stage_from_user(tape, buf, actually_written)) - ret = -EFAULT; + 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; - tape->merge_bh_size += actually_written; count -= actually_written; + tape->cur += actually_written; + tape->valid += actually_written; - if (tape->merge_bh_size == tape->buffer_size) { + if (tape->valid == tape->buffer_size) { ssize_t retval; - tape->merge_bh_size = 0; retval = idetape_add_chrdev_write_request(drive, ctl); if (retval <= 0) return (retval); @@ -1447,7 +1309,7 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, } while (count >= tape->buffer_size) { ssize_t retval; - if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size)) + if (copy_from_user(tape->cur, buf, tape->buffer_size)) ret = -EFAULT; buf += tape->buffer_size; count -= tape->buffer_size; @@ -1458,9 +1320,10 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, } if (count) { actually_written += count; - if (idetape_copy_stage_from_user(tape, buf, count)) + if (copy_from_user(tape->cur, buf, count)) ret = -EFAULT; - tape->merge_bh_size += count; + tape->cur += count; + tape->valid += count; } return ret ? ret : actually_written; } @@ -1623,7 +1486,7 @@ static int idetape_chrdev_ioctl(struct inode *inode, struct file *file, idetape_flush_tape_buffers(drive); } if (cmd == MTIOCGET || cmd == MTIOCPOS) { - block_offset = tape->merge_bh_size / + block_offset = tape->valid / (tape->blk_size * tape->user_bs_factor); position = idetape_read_position(drive); if (position < 0) @@ -1771,12 +1634,12 @@ static void idetape_write_release(ide_drive_t *drive, unsigned int minor) idetape_tape_t *tape = drive->driver_data; ide_tape_flush_merge_buffer(drive); - tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1); - if (tape->merge_bh != NULL) { + tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL); + if (tape->buf != NULL) { idetape_pad_zeros(drive, tape->blk_size * (tape->user_bs_factor - 1)); - ide_tape_kfree_buffer(tape); - tape->merge_bh = NULL; + kfree(tape->buf); + tape->buf = NULL; } idetape_write_filemark(drive); idetape_flush_tape_buffers(drive); @@ -2042,7 +1905,7 @@ static void ide_tape_release(struct device *dev) ide_drive_t *drive = tape->drive; struct gendisk *g = tape->disk; - BUG_ON(tape->merge_bh_size); + BUG_ON(tape->valid); drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP; drive->driver_data = NULL; -- 2.11.4.GIT