From 286c24028c7f2df637323e672d9aa54a07b67bde Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Wed, 27 Nov 2013 08:58:40 -0800 Subject: misc: mic: Bug fix for sysfs poll usage. MIC user space daemon poll's on sysfs changes. The documentation for sysfs_poll(...) in fs/sysfs/file.c states that "Once poll/select indicates that the value has changed, you need to close and re-open the file, or seek to 0 and read again". This step was missed out earlier and resulted in the daemon spinning continuously rather than getting blocked in 'poll'. This bug was exposed by commit aea585ef8fa65163 introduced as part of sysfs changes in 3.13-rc1. A seek to 0 has been introduced to fix it. Reviewed-by: Sudeep Dutt Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- Documentation/mic/mpssd/mpssd.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation') diff --git a/Documentation/mic/mpssd/mpssd.c b/Documentation/mic/mpssd/mpssd.c index 0c980ad40b1..5c7fdda56f0 100644 --- a/Documentation/mic/mpssd/mpssd.c +++ b/Documentation/mic/mpssd/mpssd.c @@ -1412,6 +1412,12 @@ mic_config(void *arg) } do { + ret = lseek(fd, 0, SEEK_SET); + if (ret < 0) { + mpsslog("%s: Failed to seek to file start '%s': %s\n", + mic->name, pathname, strerror(errno)); + goto close_error1; + } ret = read(fd, value, sizeof(value)); if (ret < 0) { mpsslog("%s: Failed to read sysfs entry '%s': %s\n", -- cgit v1.2.3-18-g5258