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s390/stp: add locking to sysfs functions
commit b3bd02495c
upstream.
The sysfs function might race with stp_work_fn. To prevent that,
add the required locking. Another issue is that the sysfs functions
are checking the stp_online flag, but this flag just holds the user
setting whether STP is enabled. Add a flag to clock_sync_flag whether
stp_info holds valid data and use that instead.
Cc: stable@vger.kernel.org
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
6a969548a8
commit
0bc43e64c8
1 changed files with 85 additions and 33 deletions
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@ -347,8 +347,9 @@ static DEFINE_PER_CPU(atomic_t, clock_sync_word);
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static DEFINE_MUTEX(clock_sync_mutex);
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static unsigned long clock_sync_flags;
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#define CLOCK_SYNC_HAS_STP 0
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#define CLOCK_SYNC_STP 1
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#define CLOCK_SYNC_HAS_STP 0
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#define CLOCK_SYNC_STP 1
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#define CLOCK_SYNC_STPINFO_VALID 2
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/*
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* The get_clock function for the physical clock. It will get the current
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@ -585,6 +586,22 @@ void stp_queue_work(void)
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queue_work(time_sync_wq, &stp_work);
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}
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static int __store_stpinfo(void)
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{
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int rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
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if (rc)
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clear_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
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else
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set_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
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return rc;
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}
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static int stpinfo_valid(void)
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{
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return stp_online && test_bit(CLOCK_SYNC_STPINFO_VALID, &clock_sync_flags);
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}
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static int stp_sync_clock(void *data)
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{
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struct clock_sync_data *sync = data;
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@ -606,8 +623,7 @@ static int stp_sync_clock(void *data)
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if (rc == 0) {
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sync->clock_delta = clock_delta;
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clock_sync_global(clock_delta);
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rc = chsc_sstpi(stp_page, &stp_info,
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sizeof(struct stp_sstpi));
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rc = __store_stpinfo();
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if (rc == 0 && stp_info.tmd != 2)
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rc = -EAGAIN;
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}
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@ -652,7 +668,7 @@ static void stp_work_fn(struct work_struct *work)
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if (rc)
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goto out_unlock;
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rc = chsc_sstpi(stp_page, &stp_info, sizeof(struct stp_sstpi));
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rc = __store_stpinfo();
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if (rc || stp_info.c == 0)
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goto out_unlock;
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@ -689,10 +705,14 @@ static ssize_t stp_ctn_id_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online)
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return -ENODATA;
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return sprintf(buf, "%016llx\n",
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*(unsigned long long *) stp_info.ctnid);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid())
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ret = sprintf(buf, "%016llx\n",
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*(unsigned long long *) stp_info.ctnid);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(ctn_id, 0400, stp_ctn_id_show, NULL);
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@ -701,9 +721,13 @@ static ssize_t stp_ctn_type_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online)
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return -ENODATA;
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return sprintf(buf, "%i\n", stp_info.ctn);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid())
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ret = sprintf(buf, "%i\n", stp_info.ctn);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(ctn_type, 0400, stp_ctn_type_show, NULL);
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@ -712,9 +736,13 @@ static ssize_t stp_dst_offset_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online || !(stp_info.vbits & 0x2000))
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return -ENODATA;
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return sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid() && (stp_info.vbits & 0x2000))
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ret = sprintf(buf, "%i\n", (int)(s16) stp_info.dsto);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(dst_offset, 0400, stp_dst_offset_show, NULL);
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@ -723,9 +751,13 @@ static ssize_t stp_leap_seconds_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online || !(stp_info.vbits & 0x8000))
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return -ENODATA;
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return sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid() && (stp_info.vbits & 0x8000))
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ret = sprintf(buf, "%i\n", (int)(s16) stp_info.leaps);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(leap_seconds, 0400, stp_leap_seconds_show, NULL);
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@ -734,9 +766,13 @@ static ssize_t stp_stratum_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online)
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return -ENODATA;
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return sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid())
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ret = sprintf(buf, "%i\n", (int)(s16) stp_info.stratum);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(stratum, 0400, stp_stratum_show, NULL);
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@ -745,9 +781,13 @@ static ssize_t stp_time_offset_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online || !(stp_info.vbits & 0x0800))
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return -ENODATA;
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return sprintf(buf, "%i\n", (int) stp_info.tto);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid() && (stp_info.vbits & 0x0800))
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ret = sprintf(buf, "%i\n", (int) stp_info.tto);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(time_offset, 0400, stp_time_offset_show, NULL);
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@ -756,9 +796,13 @@ static ssize_t stp_time_zone_offset_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online || !(stp_info.vbits & 0x4000))
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return -ENODATA;
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return sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid() && (stp_info.vbits & 0x4000))
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ret = sprintf(buf, "%i\n", (int)(s16) stp_info.tzo);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(time_zone_offset, 0400,
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@ -768,9 +812,13 @@ static ssize_t stp_timing_mode_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online)
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return -ENODATA;
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return sprintf(buf, "%i\n", stp_info.tmd);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid())
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ret = sprintf(buf, "%i\n", stp_info.tmd);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(timing_mode, 0400, stp_timing_mode_show, NULL);
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@ -779,9 +827,13 @@ static ssize_t stp_timing_state_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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if (!stp_online)
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return -ENODATA;
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return sprintf(buf, "%i\n", stp_info.tst);
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ssize_t ret = -ENODATA;
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mutex_lock(&stp_work_mutex);
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if (stpinfo_valid())
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ret = sprintf(buf, "%i\n", stp_info.tst);
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mutex_unlock(&stp_work_mutex);
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return ret;
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}
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static DEVICE_ATTR(timing_state, 0400, stp_timing_state_show, NULL);
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