ide-tape: improve buffer pages freeing strategy

Instead of freeing pages one by one, free them 2^order-wise. Also, mv
__idetape_kfree_stage() to ide_tape_kfree_buffer().

[bart: add updating bh->b_data]

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index ea46ed8d04479b47e2236b1308d9f18570140df3..4e93a82f57eddea5355be0501001962698de4a34 100644 (file)
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -583,20 +583,22 @@ 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);
+                       bh->b_data += (1 << order) * PAGE_SIZE;
                }
                prev_bh = bh;
                bh = bh->b_reqnext;
@@ -1373,7 +1375,7 @@ 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 +1651,7 @@ 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 +1830,7 @@ 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 +1868,7 @@ 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 +2147,7 @@ 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 +2514,7 @@ 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);