projects / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 2cb7cef9 BS |
1 | Subject: Don't require full buffer in switch_log read |
| 2 | From: Jeremy Kerr <jk@ozlabs.org> | |
| 3 | References: 447133 - LTC50070 | |
| 4 | ||
| 5 | Currently, read() on the sputrace log will block until the read buffer | |
| 6 | is full. This makes it difficult to retrieve the end of the buffer, as | |
| 7 | the user will need to read with the right-sized buffer. | |
| 8 | ||
| 9 | In a similar method as 91553a1b5e0df006a3573a88d98ee7cd48a3818a, this | |
| 10 | change makes the switch_log return if there has already been data | |
| 11 | read. | |
| 12 | ||
| 13 | Signed-off-by: Jeremy Kerr <jk@ozlabs.org> | |
| 14 | Signed-off-by: Olaf Hering <olh@suse.de> | |
| 15 | --- | |
| 16 | arch/powerpc/platforms/cell/spufs/file.c | 46 ++++++++++++++++++------------- | |
| 17 | 1 file changed, 27 insertions(+), 19 deletions(-) | |
| 18 | ||
| 19 | --- a/arch/powerpc/platforms/cell/spufs/file.c | |
| 20 | +++ b/arch/powerpc/platforms/cell/spufs/file.c | |
| 21 | @@ -2506,30 +2506,38 @@ static ssize_t spufs_switch_log_read(str | |
| 22 | char tbuf[128]; | |
| 23 | int width; | |
| 24 | ||
| 25 | - if (file->f_flags & O_NONBLOCK) { | |
| 26 | - if (spufs_switch_log_used(ctx) == 0) { | |
| 27 | + if (spufs_switch_log_used(ctx) == 0) { | |
| 28 | + if (cnt > 0) { | |
| 29 | + /* If there's data ready to go, we can | |
| 30 | + * just return straight away */ | |
| 31 | + break; | |
| 32 | + | |
| 33 | + } else if (file->f_flags & O_NONBLOCK) { | |
| 34 | error = -EAGAIN; | |
| 35 | break; | |
| 36 | + | |
| 37 | + } else { | |
| 38 | + /* spufs_wait will drop the mutex and | |
| 39 | + * re-acquire, but since we're in read(), the | |
| 40 | + * file cannot be _released (and so | |
| 41 | + * ctx->switch_log is stable). | |
| 42 | + */ | |
| 43 | + error = spufs_wait(ctx->switch_log->wait, | |
| 44 | + spufs_switch_log_used(ctx) > 0); | |
| 45 | + | |
| 46 | + /* On error, spufs_wait returns without the | |
| 47 | + * state mutex held */ | |
| 48 | + if (error) | |
| 49 | + return error; | |
| 50 | + | |
| 51 | + /* We may have had entries read from underneath | |
| 52 | + * us while we dropped the mutex in spufs_wait, | |
| 53 | + * so re-check */ | |
| 54 | + if (spufs_switch_log_used(ctx) == 0) | |
| 55 | + continue; | |
| 56 | } | |
| 57 | - } else { | |
| 58 | - /* spufs_wait will drop the mutex and re-acquire, | |
| 59 | - * but since we're in read(), the file cannot be | |
| 60 | - * _released (and so ctx->switch_log is stable). | |
| 61 | - */ | |
| 62 | - error = spufs_wait(ctx->switch_log->wait, | |
| 63 | - spufs_switch_log_used(ctx) > 0); | |
| 64 | - | |
| 65 | - /* On error, spufs_wait returns without the | |
| 66 | - * state mutex held */ | |
| 67 | - if (error) | |
| 68 | - return error; | |
| 69 | } | |
| 70 | ||
| 71 | - /* We may have had entries read from underneath us while we | |
| 72 | - * dropped the mutex in spufs_wait, so re-check */ | |
| 73 | - if (ctx->switch_log->head == ctx->switch_log->tail) | |
| 74 | - continue; | |
| 75 | - | |
| 76 | width = switch_log_sprint(ctx, tbuf, sizeof(tbuf)); | |
| 77 | if (width < len) | |
| 78 | ctx->switch_log->tail = |