projects / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 2cb7cef9 BS |
1 | From: Gerald Schaefer <geraldsc@de.ibm.com> |
| 2 | Subject: dasd: fix race in dasd timer handling | |
| 3 | References: bnc#482818,LTC#52092 | |
| 4 | ||
| 5 | Symptom: DASD driver runs into BUG statement in add_timer | |
| 6 | Problem: If the timer expires just after we check whether it is | |
| 7 | still pending and before mod_timer is called, then | |
| 8 | mod_timer will setup the timer, return zero and add_timer | |
| 9 | will be called as well although the timer is already set. | |
| 10 | Solution: Initialize the timer variables at device creation time | |
| 11 | and remove all timer_pending checks from dasd functions. | |
| 12 | del_timer and mod_timer will do all the necessary | |
| 13 | checking themselves and mod_timer will set a timer if it | |
| 14 | is not already pending. | |
| 15 | ||
| 16 | Acked-by: John Jolly <jjolly@suse.de> | |
| 17 | --- | |
| 18 | drivers/s390/block/dasd.c | 46 ++++++++++++++++------------------------------ | |
| 19 | 1 file changed, 16 insertions(+), 30 deletions(-) | |
| 20 | ||
| 21 | Index: linux-sles11/drivers/s390/block/dasd.c | |
| 22 | =================================================================== | |
| 23 | --- linux-sles11.orig/drivers/s390/block/dasd.c | |
| 24 | +++ linux-sles11/drivers/s390/block/dasd.c | |
| 25 | @@ -57,6 +57,8 @@ static void dasd_device_tasklet(struct d | |
| 26 | static void dasd_block_tasklet(struct dasd_block *); | |
| 27 | static void do_kick_device(struct work_struct *); | |
| 28 | static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *); | |
| 29 | +static void dasd_device_timeout(unsigned long); | |
| 30 | +static void dasd_block_timeout(unsigned long); | |
| 31 | ||
| 32 | /* | |
| 33 | * SECTION: Operations on the device structure. | |
| 34 | @@ -99,6 +101,8 @@ struct dasd_device *dasd_alloc_device(vo | |
| 35 | (unsigned long) device); | |
| 36 | INIT_LIST_HEAD(&device->ccw_queue); | |
| 37 | init_timer(&device->timer); | |
| 38 | + device->timer.function = dasd_device_timeout; | |
| 39 | + device->timer.data = (unsigned long) device; | |
| 40 | INIT_WORK(&device->kick_work, do_kick_device); | |
| 41 | device->state = DASD_STATE_NEW; | |
| 42 | device->target = DASD_STATE_NEW; | |
| 43 | @@ -138,6 +142,8 @@ struct dasd_block *dasd_alloc_block(void | |
| 44 | INIT_LIST_HEAD(&block->ccw_queue); | |
| 45 | spin_lock_init(&block->queue_lock); | |
| 46 | init_timer(&block->timer); | |
| 47 | + block->timer.function = dasd_block_timeout; | |
| 48 | + block->timer.data = (unsigned long) block; | |
| 49 | ||
| 50 | return block; | |
| 51 | } | |
| 52 | @@ -923,19 +929,10 @@ static void dasd_device_timeout(unsigned | |
| 53 | */ | |
| 54 | void dasd_device_set_timer(struct dasd_device *device, int expires) | |
| 55 | { | |
| 56 | - if (expires == 0) { | |
| 57 | - if (timer_pending(&device->timer)) | |
| 58 | - del_timer(&device->timer); | |
| 59 | - return; | |
| 60 | - } | |
| 61 | - if (timer_pending(&device->timer)) { | |
| 62 | - if (mod_timer(&device->timer, jiffies + expires)) | |
| 63 | - return; | |
| 64 | - } | |
| 65 | - device->timer.function = dasd_device_timeout; | |
| 66 | - device->timer.data = (unsigned long) device; | |
| 67 | - device->timer.expires = jiffies + expires; | |
| 68 | - add_timer(&device->timer); | |
| 69 | + if (expires == 0) | |
| 70 | + del_timer(&device->timer); | |
| 71 | + else | |
| 72 | + mod_timer(&device->timer, jiffies + expires); | |
| 73 | } | |
| 74 | ||
| 75 | /* | |
| 76 | @@ -943,8 +940,7 @@ void dasd_device_set_timer(struct dasd_d | |
| 77 | */ | |
| 78 | void dasd_device_clear_timer(struct dasd_device *device) | |
| 79 | { | |
| 80 | - if (timer_pending(&device->timer)) | |
| 81 | - del_timer(&device->timer); | |
| 82 | + del_timer(&device->timer); | |
| 83 | } | |
| 84 | ||
| 85 | static void dasd_handle_killed_request(struct ccw_device *cdev, | |
| 86 | @@ -1594,19 +1590,10 @@ static void dasd_block_timeout(unsigned | |
| 87 | */ | |
| 88 | void dasd_block_set_timer(struct dasd_block *block, int expires) | |
| 89 | { | |
| 90 | - if (expires == 0) { | |
| 91 | - if (timer_pending(&block->timer)) | |
| 92 | - del_timer(&block->timer); | |
| 93 | - return; | |
| 94 | - } | |
| 95 | - if (timer_pending(&block->timer)) { | |
| 96 | - if (mod_timer(&block->timer, jiffies + expires)) | |
| 97 | - return; | |
| 98 | - } | |
| 99 | - block->timer.function = dasd_block_timeout; | |
| 100 | - block->timer.data = (unsigned long) block; | |
| 101 | - block->timer.expires = jiffies + expires; | |
| 102 | - add_timer(&block->timer); | |
| 103 | + if (expires == 0) | |
| 104 | + del_timer(&block->timer); | |
| 105 | + else | |
| 106 | + mod_timer(&block->timer, jiffies + expires); | |
| 107 | } | |
| 108 | ||
| 109 | /* | |
| 110 | @@ -1614,8 +1601,7 @@ void dasd_block_set_timer(struct dasd_bl | |
| 111 | */ | |
| 112 | void dasd_block_clear_timer(struct dasd_block *block) | |
| 113 | { | |
| 114 | - if (timer_pending(&block->timer)) | |
| 115 | - del_timer(&block->timer); | |
| 116 | + del_timer(&block->timer); | |
| 117 | } | |
| 118 | ||
| 119 | /* |