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authorBorislav Petkov <petkovbb@googlemail.com>2008-04-27 09:38:25 -0400
committerBartlomiej Zolnierkiewicz <bzolnier@gmail.com>2008-04-27 09:38:25 -0400
commit97c566cebe083b8e500c9b0b5033212c809d9844 (patch)
tree9c415289280604f5fea5af3eb20da62d764fb2da /drivers/ide/ide-tape.c
parentf64eee7bb2819da5506a2db5b6297612a17eb3f8 (diff)
ide-tape: remove pipeline-specific code from idetape_add_chrdev_write_request
Refrain from adding more write requests to the pipeline and queue them directly on the device's request queue instead. [bart: re-do for minimal behavior changes] Signed-off-by: Borislav Petkov <petkovbb@gmail.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Diffstat (limited to 'drivers/ide/ide-tape.c')
-rw-r--r--drivers/ide/ide-tape.c55
1 files changed, 2 insertions, 53 deletions
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 8883eea4658f..71ebee001882 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -2202,28 +2202,16 @@ static void idetape_wait_first_stage(ide_drive_t *drive)
2202 spin_unlock_irqrestore(&tape->lock, flags); 2202 spin_unlock_irqrestore(&tape->lock, flags);
2203} 2203}
2204 2204
2205/* 2205/* Queue up a character device originated write request. */
2206 * Try to add a character device originated write request to our pipeline. In
2207 * case we don't succeed, we revert to non-pipelined operation mode for this
2208 * request. In order to accomplish that, we
2209 *
2210 * 1. Try to allocate a new pipeline stage.
2211 * 2. If we can't, wait for more and more requests to be serviced and try again
2212 * each time.
2213 * 3. If we still can't allocate a stage, fallback to non-pipelined operation
2214 * mode for this request.
2215 */
2216static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks) 2206static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
2217{ 2207{
2218 idetape_tape_t *tape = drive->driver_data; 2208 idetape_tape_t *tape = drive->driver_data;
2219 idetape_stage_t *new_stage;
2220 unsigned long flags; 2209 unsigned long flags;
2221 struct request *rq;
2222 2210
2223 debug_log(DBG_CHRDEV, "Enter %s\n", __func__); 2211 debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2224 2212
2225 /* Attempt to allocate a new stage. Beware possible race conditions. */ 2213 /* Attempt to allocate a new stage. Beware possible race conditions. */
2226 while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) { 2214 while (1) {
2227 spin_lock_irqsave(&tape->lock, flags); 2215 spin_lock_irqsave(&tape->lock, flags);
2228 if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) { 2216 if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
2229 idetape_wait_for_request(drive, tape->active_data_rq); 2217 idetape_wait_for_request(drive, tape->active_data_rq);
@@ -2234,49 +2222,10 @@ static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
2234 if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, 2222 if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE,
2235 &tape->flags)) 2223 &tape->flags))
2236 continue; 2224 continue;
2237 /*
2238 * The machine is short on memory. Fallback to non-
2239 * pipelined operation mode for this request.
2240 */
2241 return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 2225 return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
2242 blocks, tape->merge_stage->bh); 2226 blocks, tape->merge_stage->bh);
2243 } 2227 }
2244 } 2228 }
2245 rq = &new_stage->rq;
2246 idetape_init_rq(rq, REQ_IDETAPE_WRITE);
2247 /* Doesn't actually matter - We always assume sequential access */
2248 rq->sector = tape->first_frame;
2249 rq->current_nr_sectors = blocks;
2250 rq->nr_sectors = blocks;
2251
2252 idetape_switch_buffers(tape, new_stage);
2253 idetape_add_stage_tail(drive, new_stage);
2254 tape->pipeline_head++;
2255 idetape_calculate_speeds(drive);
2256
2257 /*
2258 * Estimate whether the tape has stopped writing by checking if our
2259 * write pipeline is currently empty. If we are not writing anymore,
2260 * wait for the pipeline to be almost completely full (90%) before
2261 * starting to service requests, so that we will be able to keep up with
2262 * the higher speeds of the tape.
2263 */
2264 if (!test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags)) {
2265 if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
2266 tape->nr_stages >= tape->max_stages -
2267 tape->uncontrolled_pipeline_head_speed * 3 * 1024 /
2268 tape->blk_size) {
2269 tape->measure_insert_time = 1;
2270 tape->insert_time = jiffies;
2271 tape->insert_size = 0;
2272 tape->insert_speed = 0;
2273 idetape_plug_pipeline(drive);
2274 }
2275 }
2276 if (test_and_clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags))
2277 /* Return a deferred error */
2278 return -EIO;
2279 return blocks;
2280} 2229}
2281 2230
2282/* 2231/*