summaryrefslogtreecommitdiff
AgeCommit message (Collapse)AuthorFilesLines
2014-04-08Kconfig: rename HAS_IOPORT to HAS_IOPORT_MAPUwe Kleine-König41-59/+59
If the renamed symbol is defined lib/iomap.c implements ioport_map and ioport_unmap and currently (nearly) all platforms define the port accessor functions outb/inb and friend unconditionally. So HAS_IOPORT_MAP is the better name for this. Consequently NO_IOPORT is renamed to NO_IOPORT_MAP. The motivation for this change is to reintroduce a symbol HAS_IOPORT that signals if outb/int et al are available. I will address that at least one merge window later though to keep surprises to a minimum and catch new introductions of (HAS|NO)_IOPORT. The changes in this commit were done using: $ git grep -l -E '(NO|HAS)_IOPORT' | xargs perl -p -i -e 's/\b((?:CONFIG_)?(?:NO|HAS)_IOPORT)\b/$1_MAP/' Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08ipc: use device_initcallDavidlohr Bueso3-3/+3
... since __initcall is now deprecated. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08ipc/compat.c: remove sc_semopm macroDavidlohr Bueso1-3/+0
This macro appears to have been introduced back in the 2.5 era for semtimedop32 backward compatibility on ia32: https://lkml.org/lkml/2003/4/28/78 Nowadays, this syscall in compat just defaults back to the code found in sem.c, so it is no longer used and can thus be removed: long compat_sys_semtimedop(int semid, struct sembuf __user *tsems, unsigned nsops, const struct compat_timespec __user *timeout) { struct timespec __user *ts64; if (compat_convert_timespec(&ts64, timeout)) return -EFAULT; return sys_semtimedop(semid, tsems, nsops, ts64); } Furthermore, there are no users in compat.c. After this change, kernel builds just fine with both CONFIG_SYSVIPC_COMPAT and CONFIG_SYSVIPC. Signed-off-by: Davidlohr Bueso <davidlohr@hp.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08initramfs: debug detected compression methodDaniel M. Weeks2-0/+4
This can greatly aid in narrowing down the real source of initramfs problems such as failures related to the compression of the in-kernel initramfs when an external initramfs is in use as well. Existing errors are ambiguous as to which initramfs is a problem and why. [akpm@linux-foundation.org: use pr_debug()] Signed-off-by: Daniel M. Weeks <dan@danweeks.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08fault-injection: set bounds on what /proc/self/make-it-fail accepts.Dave Jones1-0/+3
/proc/self/make-it-fail is a boolean, but accepts any number, including negative ones. Change variable to unsigned, and cap upper bound at 1. [akpm@linux-foundation.org: don't make make_it_fail unsigned] Signed-off-by: Dave Jones <davej@fedoraproject.org> Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08x86: always define BUG() and HAVE_ARCH_BUG, even with !CONFIG_BUGJosh Triplett1-3/+0
This ensures that BUG() always has a definition that causes a trap (via an undefined instruction), and that the compiler still recognizes the code following BUG() as unreachable, avoiding warnings that would otherwise appear (such as on non-void functions that don't return a value after BUG()). In addition to saving a few bytes over the generic infinite-loop implementation, this implementation traps rather than looping, which potentially allows for better error-recovery behavior (such as by rebooting). Signed-off-by: Josh Triplett <josh@joshtriplett.org> Reported-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08bug: Make BUG() always stop the machineJosh Triplett1-1/+1
When !CONFIG_BUG and !HAVE_ARCH_BUG, define the generic BUG() as an infinite loop rather than a no-op. This avoids undefined behavior if execution ever actually reaches BUG(), and avoids warnings about code after BUG() (such as on non-void functions calling BUG() and then not returning). bloat-o-meter results: add/remove: 0/0 grow/shrink: 43/10 up/down: 235/-98 (137) function old new delta umount_collect 119 138 +19 notify_change 306 324 +18 xstate_enable_boot_cpu 252 269 +17 kunmap 54 70 +16 balloon_page_dequeue 112 126 +14 mm_take_all_locks 223 233 +10 list_lru_walk_node 143 152 +9 vma_adjust 1059 1067 +8 pcpu_setup_first_chunk 1130 1138 +8 mm_drop_all_locks 143 151 +8 ns_capable 55 62 +7 anon_transport_class_unregister 8 15 +7 srcu_init_notifier_head 35 41 +6 shrink_dcache_for_umount 174 180 +6 kunmap_high 99 105 +6 end_page_writeback 43 49 +6 do_exit 1339 1345 +6 __kfifo_dma_out_prepare_r 86 92 +6 __kfifo_dma_in_prepare_r 90 96 +6 fixup_user_fault 120 125 +5 repair_env_string 73 77 +4 read_cache_pages_invalidate_page 56 60 +4 isolate_lru_pages.isra 142 146 +4 do_notify_parent_cldstop 255 259 +4 cpu_init 370 374 +4 utimes_common 270 272 +2 tasklet_hi_action 91 93 +2 tasklet_action 91 93 +2 set_pte_vaddr 46 48 +2 find_get_pages_tag 202 204 +2 early_iounmap 185 187 +2 __native_set_fixmap 36 38 +2 __get_user_pages 822 824 +2 __early_ioremap 299 301 +2 yield_task_stop 1 2 +1 tick_resume 37 38 +1 switched_to_stop 1 2 +1 switched_to_idle 1 2 +1 prio_changed_stop 1 2 +1 prio_changed_idle 1 2 +1 pm_qos_power_read 111 112 +1 arch_cpu_idle_dead 1 2 +1 __insert_vmap_area 140 141 +1 sys_renameat 614 612 -2 mm_fault_error 297 295 -2 SyS_renameat 614 612 -2 sys_linkat 416 413 -3 SyS_linkat 416 413 -3 chmod_common 129 122 -7 proc_cap_handler 240 225 -15 __schedule 849 831 -18 sys_madvise 1077 1054 -23 SyS_madvise 1077 1054 -23 Signed-off-by: Josh Triplett <josh@joshtriplett.org> Reported-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08bug: when !CONFIG_BUG, make WARN call no_printk to check format and argsJosh Triplett1-0/+1
The stub version of WARN for !CONFIG_BUG completely ignored its format string and subsequent arguments; make it check them instead, using no_printk. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Reported-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08include/asm-generic/bug.h: style fix: s/while(0)/while (0)/Josh Triplett1-3/+3
Signed-off-by: Josh Triplett <josh@joshtriplett.org> Reported-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08bug: when !CONFIG_BUG, simplify WARN_ON_ONCE and familyJosh Triplett1-27/+30
When !CONFIG_BUG, WARN_ON and family become simple passthroughs of their condition argument; however, WARN_ON_ONCE and family still have conditions and a boolean to detect one-time invocation, even though the warning they'd emit doesn't exist. Make the existing definitions conditional on CONFIG_BUG, and add definitions for !CONFIG_BUG that map to the passthrough versions of WARN and WARN_ON. This saves 4.4k on a minimized configuration (smaller than allnoconfig), and 20.6k with defconfig plus CONFIG_BUG=n. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08kconfig: make allnoconfig disable options behind EMBEDDED and EXPERTJosh Triplett8-6/+25
"make allnoconfig" exists to ease testing of minimal configurations. Documentation/SubmitChecklist includes a note to test with allnoconfig. This helps catch missing dependencies on common-but-not-required functionality, which might otherwise go unnoticed. However, allnoconfig still leaves many symbols enabled, because they're hidden behind CONFIG_EMBEDDED or CONFIG_EXPERT. For instance, allnoconfig still has CONFIG_PRINTK and CONFIG_BLOCK enabled, so drivers don't typically get build-tested with those disabled. To address this, introduce a new Kconfig option "allnoconfig_y", used on symbols which only exist to hide other symbols. Set it on CONFIG_EMBEDDED (which then selects CONFIG_EXPERT). allnoconfig will then disable all the symbols hidden behind those. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08ppc: make PPC_BOOK3S_64 select IRQ_WORKJosh Triplett1-0/+1
Fix breakage which will be exposed by the patch "kconfig: make allnoconfig disable options behind EMBEDDED and EXPERT". arch/powerpc/kernel/mce.c, compiled in for PPC_BOOK3S_64, calls functions only built when IRQ_WORK, so select it. Fixes the following build error: arch/powerpc/kernel/built-in.o: In function `.machine_check_queue_event': (.text+0x11260): undefined reference to `.irq_work_queue' Signed-off-by: Josh Triplett <josh@joshtriplett.org> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08ia64: select CONFIG_TTY for use of tty_write_message in unalignedJosh Triplett1-0/+1
Fix breakage which will be exposed by the patch "kconfig: make allnoconfig disable options behind EMBEDDED and EXPERT". arch/ia64/kernel/unaligned.c uses tty_write_message to print an unaligned access exception to the TTY of the current user process. Enable TTY to prevent a build error. Minimal fix, on the basis that few people on ia64 will care deeply about kernel size enough to turn off TTY. Ideally, I'd instead suggest dropping the tty_write_message entirely, and just leaving the printk. Bonus: no need to sprintf first. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08cris: cpuinfo_op should depend on CONFIG_PROC_FSGeert Uytterhoeven1-0/+2
Fix breakage which will be exposed by the patch "kconfig: make allnoconfig disable options behind EMBEDDED and EXPERT". Now allnoconfig started disabling CONFIG_PROC_FS: arch/cris/kernel/built-in.o:(.rodata+0xc): undefined reference to `show_cpuinfo' make: *** [vmlinux] Error 1 Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08cris: make ETRAX_ARCH_V10 select TTY for use in debugportJosh Triplett1-0/+1
Fix breakage which will be exposed by the patch "kconfig: make allnoconfig disable options behind EMBEDDED and EXPERT". arch/cris/arch-v10/kernel/debugport.c, compiled in unconditionally with ETRAX_ARCH_V10, requires TTY, so select TTY to avoid a build failure. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08drivers/misc/sgi-gru/grukdump.c: cleanup gru_dump_context() a littleDan Carpenter1-3/+3
"ret" is zero here so we can remove the "!ret" part of the condition. "uhdr" is alread a __user pointer so we can remove the cast. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Dimitri Sivanich <sivanich@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08kernel/panic.c: display reason at end + pr_emergFabian Frederick1-7/+6
Currently, booting without initrd specified on 80x25 screen gives a call trace followed by atkbd : Spurious ACK. Original message ("VFS: Unable to mount root fs") is not available. Of course this could happen in other situations... This patch displays panic reason after call trace which could help lot of people even if it's not the very last line on screen. Also, convert all panic.c printk(KERN_EMERG to pr_emerg( [akpm@linux-foundation.org: missed a couple of pr_ conversions] Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08fs/bfs/inode.c: add __init to init_inodecache()Fabian Frederick1-1/+1
init_inodecache is only called by __init init_bfs_fs Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08affs: add mount option to avoid filename truncatesFabian Frederick5-33/+57
Normal behavior for filenames exceeding specific filesystem limits is to refuse operation. AFFS standard name length being only 30 characters against 255 for usual Linux filesystems, original implementation does filename truncate by default with a define value AFFS_NO_TRUNCATE which can be enabled but needs module compilation. This patch adds 'nofilenametruncate' mount option so that user can easily activate that feature and avoid a lot of problems (eg overwrite files ...) Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08fs/affs/dir.c: unlock/brelse dir on failure + code clean-upFabian Frederick1-10/+18
Commit 0edf977d2ae3 ("[readdir] convert affs") returns directly -EIO without unlocking dir inode and releasing dir bh when second affs_bread sequence fails. This patch restores initial behaviour. It also fixes pr_debug and affs_error to fit in 80 columns + removes reference to filldir (replaced by dir_emit in the commit above). Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08affs: add __init to init_inodecache ()Fabian Frederick1-1/+1
init_inodecache is only called by __init init_affs_fs Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08fs/adfs/super.c: add __init to init_inodecache()Fabian Frederick1-1/+1
init_inodecache is only called by __init init_adfs_fs. Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08hung_task: check the value of "sysctl_hung_task_timeout_sec"Liu Hua2-0/+7
As sysctl_hung_task_timeout_sec is unsigned long, when this value is larger then LONG_MAX/HZ, the function schedule_timeout_interruptible in watchdog will return immediately without sleep and with print : schedule_timeout: wrong timeout value ffffffffffffff83 and then the funtion watchdog will call schedule_timeout_interruptible again and again. The screen will be filled with "schedule_timeout: wrong timeout value ffffffffffffff83" This patch does some check and correction in sysctl, to let the function schedule_timeout_interruptible allways get the valid parameter. Signed-off-by: Liu Hua <sdu.liu@huawei.com> Tested-by: Satoru Takeuchi <satoru.takeuchi@gmail.com> Cc: <stable@vger.kernel.org> [3.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08rapidio: rework device hierarchy and introduce mport class of devicesAlexandre Bounine10-16/+133
This patch removes an artificial RapidIO bus root device and establishes actual device hierarchy by providing reference to real parent devices. It also introduces device class for RapidIO controller devices (on-chip or an eternal bridge, known as "mport"). Existing implementation was sufficient for SoC-based platforms that have a single RapidIO controller. With introduction of devices using multiple RapidIO controllers and PCIe-to-RapidIO bridges the old scheme is very limiting or does not work at all. The implemented changes allow to properly reference platform's local RapidIO mport devices and provide device details needed for upper layers. This change to RapidIO device hierarchy does not break any known existing kernel or user space interfaces. Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Li Yang <leoli@freescale.com> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com> Cc: Stef van Os <stef.van.os@prodrive-technologies.com> Cc: Jerry Jacobs <jerry.jacobs@prodrive-technologies.com> Cc: Arno Tiemersma <arno.tiemersma@prodrive-technologies.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08drivers/rapidio/devices/tsi721_dma.c: optimize use of BDMA descriptorsAlexandre Bounine2-33/+82
Combine SG entries describing single contiguous memory block into one Tsi721 BDMA descriptor. This reduces number of hardware descriptors required for large data transfers and improves performance on the PCIe side by reducing number of descriptor fetch requests. Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com> Cc: Matt Porter <mporter@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08lib/idr.c: use RCU_INIT_POINTER(x, NULL)Monam Agarwal1-2/+2
Replace rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL) The rcu_assign_pointer() ensures that the initialization of a structure is carried out before storing a pointer to that structure. And in the case of the NULL pointer, there is no structure to initialize. So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL) Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08idr: remove dead codeStephen Hemminger2-81/+2
Remove no longer used deprecated code, and make local functions static. Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Acked-by: Jean Delvare <jdelvare@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Cc: Jeff Layton <jlayton@redhat.com> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: George Spelvin <linux@horizon.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08vmcore: continue vmcore initialization if PT_NOTE is found emptyWANG Chao1-2/+0
Currently when an empty PT_NOTE is detected, vmcore initialization fails. It sounds too harsh. Because PT_NOTE could be empty, for example, one offlined a cpu but never restarted kdump service, and after crash, PT_NOTE program header is there but no data contains. It's better to warn about the empty PT_NOTE and continue to initialise vmcore. And ultimately the multiple PT_NOTE are merged into a single one, all empty PT_NOTE are discarded naturally during the merge. So empty PT_NOTE is not visible to user space and vmcore is as good as expected. Signed-off-by: WANG Chao <chaowang@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Cc: Greg Pearson <greg.pearson@hp.com> Cc: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08include/linux/crash_dump.h: add vmcore_cleanup() prototypeRashika Kheria3-2/+1
Eliminate the following warning in proc/vmcore.c: fs/proc/vmcore.c:1088:6: warning: no previous prototype for `vmcore_cleanup' [-Wmissing-prototypes] [akpm@linux-foundation.org: clean up powerpc, remove unneeded EXPORT_SYMBOL] Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08wait: WSTOPPED|WCONTINUED doesn't work if a zombie leader is traced by ↵Oleg Nesterov1-13/+9
another process Even if the main thread is dead the process still can stop/continue. However, if the leader is ptraced wait_consider_task(ptrace => false) always skips wait_task_stopped/wait_task_continued, so WSTOPPED or WCONTINUED can never work for the natural parent in this case. Move the "A zombie ptracee is only visible to its ptracer" check into the "if (!delay_group_leader(p))" block. ->notask_error is cleared by the "fall through" code below. This depends on the previous change, wait_task_stopped/continued must be avoided if !delay_group_leader() and the tracer is ->real_parent. Otherwise WSTOPPED|WEXITED could wrongly report "stopped" when the child is already dead (single-threaded or not). If it is traced by another task then the "stopped" state is fine until the debugger detaches and reveals a zombie state. Stupid test-case: void *tfunc(void *arg) { sleep(1); // wait for zombie leader raise(SIGSTOP); exit(0x13); return NULL; } int run_child(void) { pthread_t thread; if (!fork()) { int tracee = getppid(); assert(ptrace(PTRACE_ATTACH, tracee, 0,0) == 0); do ptrace(PTRACE_CONT, tracee, 0,0); while (wait(NULL) > 0); return 0; } sleep(1); // wait for PTRACE_ATTACH assert(pthread_create(&thread, NULL, tfunc, NULL) == 0); pthread_exit(NULL); } int main(void) { int child, stat; child = fork(); if (!child) return run_child(); assert(child == waitpid(-1, &stat, WSTOPPED)); assert(stat == 0x137f); kill(child, SIGCONT); assert(child == waitpid(-1, &stat, WCONTINUED)); assert(stat == 0xffff); assert(child == waitpid(-1, &stat, 0)); assert(stat == 0x1300); return 0; } Without this patch it hangs in waitpid(WSTOPPED), wait_task_stopped() is never called. Note: this doesn't fix all problems with a zombie delay_group_leader(), WCONTINUED | WEXITED check is not exactly right. debugger can't assume it will be notified if another thread reaps the whole thread group. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08wait: WSTOPPED|WCONTINUED hangs if a zombie child is traced by real_parentOleg Nesterov1-13/+16
"A zombie is only visible to its ptracer" logic in wait_consider_task() is very wrong. Trivial test-case: #include <unistd.h> #include <sys/ptrace.h> #include <sys/wait.h> #include <assert.h> int main(void) { int child = fork(); if (!child) { assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0); return 0x23; } assert(waitid(P_ALL, child, NULL, WEXITED | WNOWAIT) == 0); assert(waitid(P_ALL, 0, NULL, WSTOPPED) == -1); return 0; } it hangs in waitpid(WSTOPPED) despite the fact it has a single zombie child. This is because wait_consider_task(ptrace => 0) sees p->ptrace and cleares ->notask_error assuming that the debugger should detach and notify us. Change wait_consider_task(ptrace => 0) to pretend that ptrace == T if the child is traced by us. This really simplifies the logic and allows us to do more fixes, see the next changes. This also hides the unwanted group stop state automatically, we can remove another ptrace_reparented() check. Unfortunately, this adds the following behavioural changes: 1. Before this patch wait(WEXITED | __WNOTHREAD) does not reap a natural child if it is traced by the caller's sub-thread. Hopefully nobody will ever notice this change, and I think that nobody should rely on this behaviour anyway. 2. SIGNAL_STOP_CONTINUED is no longer hidden from debugger if it is real parent. While this change comes as a side effect, I think it is good by itself. The group continued state can not be consumed by another process in this case, it doesn't depend on ptrace, it doesn't make sense to hide it from real parent. Perhaps we should add the thread_group_leader() check before wait_task_continued()? May be, but this shouldn't depend on ptrace_reparented(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08wait: swap EXIT_ZOMBIE and EXIT_DEAD to hide EXIT_TRACE from user-spaceOleg Nesterov2-4/+4
get_task_state() uses the most significant bit to report the state to user-space, this means that EXIT_ZOMBIE->EXIT_TRACE->EXIT_DEAD transition can be noticed via /proc as Z -> X -> Z change. Note that this was possible even before EXIT_TRACE was introduced. This is not really bad but imho it make sense to hide EXIT_TRACE from user-space completely. So the patch simply swaps EXIT_ZOMBIE and EXIT_DEAD, this way EXIT_TRACE will be seen as EXIT_ZOMBIE by user-space. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08wait: completely ignore the EXIT_DEAD tasksOleg Nesterov1-5/+6
Now that EXIT_DEAD is the terminal state it doesn't make sense to call eligible_child() or security_task_wait() if the task is really dead. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08wait: use EXIT_TRACE only if thread_group_leader(zombie)Oleg Nesterov1-10/+7
wait_task_zombie() always uses EXIT_TRACE/ptrace_unlink() if ptrace_reparented(). This is suboptimal and a bit confusing: we do not need do_notify_parent(p) if !thread_group_leader(p) and in this case we also do not need ptrace_unlink(), we can rely on ptrace_release_task(). Change wait_task_zombie() to check thread_group_leader() along with ptrace_reparented() and simplify the final p->exit_state transition. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08wait: introduce EXIT_TRACE to avoid the racy EXIT_DEAD->EXIT_ZOMBIE transitionOleg Nesterov2-29/+22
wait_task_zombie() first does EXIT_ZOMBIE->EXIT_DEAD transition and drops tasklist_lock. If this task is not the natural child and it is traced, we change its state back to EXIT_ZOMBIE for ->real_parent. The last transition is racy, this is even documented in 50b8d257486a "ptrace: partially fix the do_wait(WEXITED) vs EXIT_DEAD->EXIT_ZOMBIE race". wait_consider_task() tries to detect this transition and clear ->notask_error but we can't rely on ptrace_reparented(), debugger can exit and do ptrace_unlink() before its sub-thread sets EXIT_ZOMBIE. And there is another problem which were missed before: this transition can also race with reparent_leader() which doesn't reset >exit_signal if EXIT_DEAD, assuming that this task must be reaped by someone else. So the tracee can be re-parented with ->exit_signal != SIGCHLD, and if /sbin/init doesn't use __WALL it becomes unreapable. This was fixed by the previous commit, but it was the temporary hack. 1. Add the new exit_state, EXIT_TRACE. It means that the task is the traced zombie, debugger is going to detach and notify its natural parent. This new state is actually EXIT_ZOMBIE | EXIT_DEAD. This way we can avoid the changes in proc/kgdb code, get_task_state() still reports "X (dead)" in this case. Note: with or without this change userspace can see Z -> X -> Z transition. Not really bad, but probably makes sense to fix. 2. Change wait_task_zombie() to use EXIT_TRACE instead of EXIT_DEAD if we need to notify the ->real_parent. 3. Revert the previous hack in reparent_leader(), now that EXIT_DEAD is always the final state we can safely ignore such a task. 4. Change wait_consider_task() to check EXIT_TRACE separately and kill the racy and no longer needed ptrace_reparented() case. If ptrace == T an EXIT_TRACE thread should be simply ignored, the owner of this state is going to ptrace_unlink() this task. We can pretend that it was already removed from ->ptraced list. Otherwise we should skip this thread too but clear ->notask_error, we must be the natural parent and debugger is going to untrace and notify us. IOW, this doesn't differ from "EXIT_ZOMBIE && p->ptrace" even if the task was already untraced. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Jan Kratochvil <jan.kratochvil@redhat.com> Reported-by: Michal Schmidt <mschmidt@redhat.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08wait: fix reparent_leader() vs EXIT_DEAD->EXIT_ZOMBIE raceOleg Nesterov1-4/+11
wait_task_zombie() first does EXIT_ZOMBIE->EXIT_DEAD transition and drops tasklist_lock. If this task is not the natural child and it is traced, we change its state back to EXIT_ZOMBIE for ->real_parent. The last transition is racy, this is even documented in 50b8d257486a "ptrace: partially fix the do_wait(WEXITED) vs EXIT_DEAD->EXIT_ZOMBIE race". wait_consider_task() tries to detect this transition and clear ->notask_error but we can't rely on ptrace_reparented(), debugger can exit and do ptrace_unlink() before its sub-thread sets EXIT_ZOMBIE. And there is another problem which were missed before: this transition can also race with reparent_leader() which doesn't reset >exit_signal if EXIT_DEAD, assuming that this task must be reaped by someone else. So the tracee can be re-parented with ->exit_signal != SIGCHLD, and if /sbin/init doesn't use __WALL it becomes unreapable. Change reparent_leader() to update ->exit_signal even if EXIT_DEAD. Note: this is the simple temporary hack for -stable, it doesn't try to solve all problems, it will be reverted by the next changes. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Jan Kratochvil <jan.kratochvil@redhat.com> Reported-by: Michal Schmidt <mschmidt@redhat.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08exec: kill bprm->tcomm[], simplify the "basename" logicOleg Nesterov4-22/+4
Starting from commit c4ad8f98bef7 ("execve: use 'struct filename *' for executable name passing") bprm->filename can not go away after flush_old_exec(), so we do not need to save the binary name in bprm->tcomm[] added by 96e02d158678 ("exec: fix use-after-free bug in setup_new_exec()"). And there was never need for filename_to_taskname-like code, we can simply do set_task_comm(kbasename(filename). This patch has to change set_task_comm() and trace_task_rename() to accept "const char *", but I think this change is also good. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08procfs: make /proc/*/pagemap 0400Djalal Harouni1-2/+2
The /proc/*/pagemap contain sensitive information and currently its mode is 0444. Change this to 0400, so the VFS will prevent unprivileged processes from getting file descriptors on arbitrary privileged /proc/*/pagemap files. This reduces the scope of address space leaking and bypasses by protecting already running processes. Signed-off-by: Djalal Harouni <tixxdz@opendz.org> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Andy Lutomirski <luto@amacapital.net> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08procfs: make /proc/*/{stack,syscall,personality} 0400Djalal Harouni1-6/+6
These procfs files contain sensitive information and currently their mode is 0444. Change this to 0400, so the VFS will be able to block unprivileged processes from getting file descriptors on arbitrary privileged /proc/*/{stack,syscall,personality} files. This reduces the scope of ASLR leaking and bypasses by protecting already running processes. Signed-off-by: Djalal Harouni <tixxdz@opendz.org> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Andy Lutomirski <luto@amacapital.net> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08fs/proc/inode.c: use RCU_INIT_POINTER(x, NULL)Monam Agarwal1-1/+1
Replace rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL) The rcu_assign_pointer() ensures that the initialization of a structure is carried out before storing a pointer to that structure. And in the case of the NULL pointer, there is no structure to initialize. So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL) Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08proc: show mnt_id in /proc/pid/fdinfoAndrey Vagin2-7/+16
Currently we don't have a way how to determing from which mount point file has been opened. This information is required for proper dumping and restoring file descriptos due to presence of mount namespaces. It's possible, that two file descriptors are opened using the same paths, but one fd references mount point from one namespace while the other fd -- from other namespace. $ ls -l /proc/1/fd/1 lrwx------ 1 root root 64 Mar 19 23:54 /proc/1/fd/1 -> /dev/null $ cat /proc/1/fdinfo/1 pos: 0 flags: 0100002 mnt_id: 16 $ cat /proc/1/mountinfo | grep ^16 16 32 0:4 / /dev rw,nosuid shared:2 - devtmpfs devtmpfs rw,size=1013356k,nr_inodes=253339,mode=755 Signed-off-by: Andrey Vagin <avagin@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Rob Landley <rob@landley.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08fs/proc/meminfo: meminfo_proc_show(): fix typo in commentLuiz Capitulino1-1/+1
It should read "reclaimable slab" and not "reclaimable swap". Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08kernel/exit.c: call proc_exit_connector() after exit_state is setGuillaume Morin1-1/+1
The process events connector delivers a notification when a process exits. This is really convenient for a process that spawns and wants to monitor its children through an epoll-able() interface. Unfortunately, there is a small window between when the event is delivered and the child become wait()-able. This is creates a race if the parent wants to make sure that it knows about the exit, e.g pid_t pid = fork(); if (pid > 0) { register_interest_for_pid(pid); if (waitpid(pid, NULL, WNOHANG) > 0) { /* We might have raced with exit() */ } return; } /* Child */ execve(...) register_interest_for_pid() would be telling the the connector socket reader to pay attention to events related to pid. Though this is not a bug, I think it would make the connector a bit more usable if this race was closed by simply moving the call to proc_exit_connector() from just before exit_notify() to right after. Oleg said: : Even with this patch the code above is still "racy" if the child is : multi-threaded. Plus it should obviously filter-out subthreads. And : afaics there is no way to make it reliable, even if you change the code : above so that waitpid() is called only after the last thread exits WNOHANG : still can fail. Signed-off-by: Guillaume Morin <guillaume@morinfr.org> Cc: Matt Helsley <matt.helsley@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08exit: move check_stack_usage() to the end of do_exit()Oleg Nesterov1-1/+1
It is not clear why check_stack_usage() is called so early and thus it never checks the stack usage in, say, exit_notify() or flush_ptrace_hw_breakpoint() or other functions which are only called by do_exit(). Move the callsite down to the last preempt_disable/schedule. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08exit: call disassociate_ctty() before exit_task_namespaces()Oleg Nesterov1-4/+2
Commit 8aac62706ada ("move exit_task_namespaces() outside of exit_notify()") breaks pppd and the exiting service crashes the kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 IP: ppp_register_channel+0x13/0x20 [ppp_generic] Call Trace: ppp_asynctty_open+0x12b/0x170 [ppp_async] tty_ldisc_open.isra.2+0x27/0x60 tty_ldisc_hangup+0x1e3/0x220 __tty_hangup+0x2c4/0x440 disassociate_ctty+0x61/0x270 do_exit+0x7f2/0xa50 ppp_register_channel() needs ->net_ns and current->nsproxy == NULL. Move disassociate_ctty() before exit_task_namespaces(), it doesn't make sense to delay it after perf_event_exit_task() or cgroup_exit(). This also allows to use task_work_add() inside the (nontrivial) code paths in disassociate_ctty(). Investigated by Peter Hurley. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Sree Harsha Totakura <sreeharsha@totakura.in> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Sree Harsha Totakura <sreeharsha@totakura.in> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Andrey Vagin <avagin@openvz.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> [v3.10+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08mm/zswap.c: remove unnecessary parenthesesSeongJae Park1-3/+3
Fix following trivial checkpatch error: ERROR: return is not a function, parentheses are not required Signed-off-by: SeongJae Park <sj38.park@gmail.com> Acked-by: Seth Jennings <sjennings@variantweb.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08mm/zswap: support multiple swap devicesMinchan Kim1-31/+33
Cai Liu reporeted that now zbud pool pages counting has a problem when multiple swap is used because it just counts only one swap intead of all of swap so zswap cannot control writeback properly. The result is unnecessary writeback or no writeback when we should really writeback. IOW, it made zswap crazy. Another problem in zswap is: For example, let's assume we use two swap A and B with different priority and A already has charged 19% long time ago and let's assume that A swap is full now so VM start to use B so that B has charged 1% recently. It menas zswap charged (19% + 1%) is full by default. Then, if VM want to swap out more pages into B, zbud_reclaim_page would be evict one of pages in B's pool and it would be repeated continuously. It's totally LRU reverse problem and swap thrashing in B would happen. This patch makes zswap consider mutliple swap by creating *a* zbud pool which will be shared by multiple swap so all of zswap pages in multiple swap keep order by LRU so it can prevent above two problems. Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Cai Liu <cai.liu@samsung.com> Suggested-by: Weijie Yang <weijie.yang.kh@gmail.com> Cc: Seth Jennings <sjennings@variantweb.net> Reviewed-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08mm/zswap.c: update zsmalloc in comment to zbudSeongJae Park1-2/+2
zswap used zsmalloc before and now using zbud. But, some comments saying it use zsmalloc yet. Fix the trivial problems. Signed-off-by: SeongJae Park <sj38.park@gmail.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08mm/zswap.c: fix trivial typo and arrange indentationSeongJae Park1-2/+2
Signed-off-by: SeongJae Park <sj38.park@gmail.com> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-08zram: support REQ_DISCARDJoonsoo Kim1-0/+62
zram is ram based block device and can be used by backend of filesystem. When filesystem deletes a file, it normally doesn't do anything on data block of that file. It just marks on metadata of that file. This behavior has no problem on disk based block device, but has problems on ram based block device, since we can't free memory used for data block. To overcome this disadvantage, there is REQ_DISCARD functionality. If block device support REQ_DISCARD and filesystem is mounted with discard option, filesystem sends REQ_DISCARD to block device whenever some data blocks are discarded. All we have to do is to handle this request. This patch implements to flag up QUEUE_FLAG_DISCARD and handle this REQ_DISCARD request. With it, we can free memory used by zram if it isn't used. [akpm@linux-foundation.org: tweak comments] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-22 13:49:16 +0300