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Subject[PATCH 4/5] ide-tape: improve buffer pages freeing strategy
Date
From
Instead of freeing pages one by one, free them 2^order-wise. Also, mv
__idetape_kfree_stage() to ide_tape_kfree_buffer().

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
---
drivers/ide/ide-tape.c | 37 +++++++++++++++++++------------------
1 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index cf4351c..dcaefef 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -583,20 +583,21 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
}
}

-/* Free a stage along with its related buffers completely. */
-static void __idetape_kfree_stage(idetape_stage_t *stage)
+/* Free data buffers completely. */
+static void ide_tape_kfree_buffer(idetape_stage_t *stage)
{
struct idetape_bh *prev_bh, *bh = stage->bh;
- int size;
-
- while (bh != NULL) {
- if (bh->b_data != NULL) {
- size = (int) bh->b_size;
- while (size > 0) {
- free_page((unsigned long) bh->b_data);
- size -= PAGE_SIZE;
- bh->b_data += PAGE_SIZE;
- }
+
+ while (bh) {
+ u32 size = bh->b_size;
+
+ while (size) {
+ unsigned int order = fls(size >> PAGE_SHIFT)-1;
+
+ if (bh->b_data)
+ free_pages((unsigned long)bh->b_data, order);
+
+ size &= (order-1);
}
prev_bh = bh;
bh = bh->b_reqnext;
@@ -1373,7 +1374,7 @@ static idetape_stage_t *ide_tape_kmalloc_buffer(idetape_tape_t *tape, int full,
atomic_sub(tape->excess_bh_size, &bh->b_count);
return stage;
abort:
- __idetape_kfree_stage(stage);
+ ide_tape_kfree_buffer(stage);
return NULL;
}

@@ -1649,7 +1650,7 @@ static int __idetape_discard_read_pipeline(ide_drive_t *drive)
clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
tape->merge_stage_size = 0;
if (tape->merge_stage != NULL) {
- __idetape_kfree_stage(tape->merge_stage);
+ ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
}

@@ -1828,7 +1829,7 @@ static void idetape_empty_write_pipeline(ide_drive_t *drive)
tape->merge_stage_size = 0;
}
if (tape->merge_stage != NULL) {
- __idetape_kfree_stage(tape->merge_stage);
+ ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
}
tape->chrdev_dir = IDETAPE_DIR_NONE;
@@ -1866,7 +1867,7 @@ static int idetape_init_read(ide_drive_t *drive)
REQ_IDETAPE_READ, 0,
tape->merge_stage->bh);
if (bytes_read < 0) {
- __idetape_kfree_stage(tape->merge_stage);
+ ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
tape->chrdev_dir = IDETAPE_DIR_NONE;
return bytes_read;
@@ -2145,7 +2146,7 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
REQ_IDETAPE_WRITE, 0,
tape->merge_stage->bh);
if (retval < 0) {
- __idetape_kfree_stage(tape->merge_stage);
+ ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
tape->chrdev_dir = IDETAPE_DIR_NONE;
return retval;
@@ -2512,7 +2513,7 @@ static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
if (tape->merge_stage != NULL) {
idetape_pad_zeros(drive, tape->blk_size *
(tape->user_bs_factor - 1));
- __idetape_kfree_stage(tape->merge_stage);
+ ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
}
idetape_write_filemark(drive);
--
1.5.4.1


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