From: Minchan Kim <minchan@xxxxxxxxxx> Subject: mm: use only pidfd for process_madvise syscall Based on discussion[1], people didn't feel we need to support both pid and pidfd for every new coming API[2] so this patch keeps only pidfd. This patch also changes flags's type with "unsigned int". [1] https://lore.kernel.org/linux-mm/20200509124817.xmrvsrq3mla6b76k@wittgenstein/ [2] https://lore.kernel.org/linux-mm/9d849087-3359-c4ab-fbec-859e8186c509@xxxxxxxxxxxxx/ [minchan@xxxxxxxxxx: return EBADF if pidfd is invalid] Link: http://lkml.kernel.org/r/20200519181447.GA220547@xxxxxxxxxx Link: http://lkml.kernel.org/r/20200518211350.GA50295@xxxxxxxxxx Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Arjun Roy <arjunroy@xxxxxxxxxx> Cc: Tim Murray <timmurray@xxxxxxxxxx> Cc: Daniel Colascione <dancol@xxxxxxxxxx> Cc: Sonny Rao <sonnyrao@xxxxxxxxxx> Cc: Brian Geffon <bgeffon@xxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: John Dias <joaodias@xxxxxxxxxx> Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> Cc: SeongJae Park <sj38.park@xxxxxxxxx> Cc: Oleksandr Natalenko <oleksandr@xxxxxxxxxx> Cc: Sandeep Patil <sspatil@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Christian Brauner <christian.brauner@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/compat.h | 6 ++--- include/linux/syscalls.h | 5 +--- mm/madvise.c | 41 +++++++++---------------------------- 3 files changed, 16 insertions(+), 36 deletions(-) --- a/include/linux/compat.h~mm-use-only-pidfd-for-process_madvise-syscall +++ a/include/linux/compat.h @@ -827,10 +827,10 @@ asmlinkage long compat_sys_pwritev64v2(u unsigned long vlen, loff_t pos, rwf_t flags); #endif -asmlinkage ssize_t compat_sys_process_madvise(compat_int_t which, - compat_pid_t upid, const struct compat_iovec __user *vec, +asmlinkage ssize_t compat_sys_process_madvise(compat_int_t pidfd, + const struct compat_iovec __user *vec, compat_ulong_t vlen, compat_int_t behavior, - compat_ulong_t flags); + compat_int_t flags); /* * Deprecated system calls which are still defined in --- a/include/linux/syscalls.h~mm-use-only-pidfd-for-process_madvise-syscall +++ a/include/linux/syscalls.h @@ -878,9 +878,8 @@ asmlinkage long sys_munlockall(void); asmlinkage long sys_mincore(unsigned long start, size_t len, unsigned char __user * vec); asmlinkage long sys_madvise(unsigned long start, size_t len, int behavior); -asmlinkage long sys_process_madvise(int which, pid_t upid, - const struct iovec __user *vec, unsigned long vlen, - int behavior, unsigned long flags); +asmlinkage long sys_process_madvise(int pidfd, const struct iovec __user *vec, + unsigned long vlen, int behavior, unsigned int flags); asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size, unsigned long prot, unsigned long pgoff, unsigned long flags); --- a/mm/madvise.c~mm-use-only-pidfd-for-process_madvise-syscall +++ a/mm/madvise.c @@ -1230,8 +1230,8 @@ static int process_madvise_vec(struct ta return ret; } -static ssize_t do_process_madvise(int which, pid_t upid, struct iov_iter *iter, - int behavior, unsigned long flags) +static ssize_t do_process_madvise(int pidfd, struct iov_iter *iter, + int behavior, unsigned int flags) { ssize_t ret; struct pid *pid; @@ -1242,26 +1242,9 @@ static ssize_t do_process_madvise(int wh if (flags != 0) return -EINVAL; - switch (which) { - case P_PID: - if (upid <= 0) - return -EINVAL; - - pid = find_get_pid(upid); - if (!pid) - return -ESRCH; - break; - case P_PIDFD: - if (upid < 0) - return -EINVAL; - - pid = pidfd_get_pid(upid); - if (IS_ERR(pid)) - return PTR_ERR(pid); - break; - default: - return -EINVAL; - } + pid = pidfd_get_pid(pidfd); + if (IS_ERR(pid)) + return PTR_ERR(pid); task = get_pid_task(pid, PIDTYPE_PID); if (!task) { @@ -1293,9 +1276,8 @@ put_pid: return ret; } -SYSCALL_DEFINE6(process_madvise, int, which, pid_t, upid, - const struct iovec __user *, vec, unsigned long, vlen, - int, behavior, unsigned long, flags) +SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, + unsigned long, vlen, int, behavior, unsigned int, flags) { ssize_t ret; struct iovec iovstack[UIO_FASTIOV]; @@ -1304,19 +1286,18 @@ SYSCALL_DEFINE6(process_madvise, int, wh ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); if (ret >= 0) { - ret = do_process_madvise(which, upid, &iter, behavior, flags); + ret = do_process_madvise(pidfd, &iter, behavior, flags); kfree(iov); } return ret; } #ifdef CONFIG_COMPAT -COMPAT_SYSCALL_DEFINE6(process_madvise, compat_int_t, which, - compat_pid_t, upid, +COMPAT_SYSCALL_DEFINE5(process_madvise, compat_int_t, pidfd, const struct compat_iovec __user *, vec, compat_ulong_t, vlen, compat_int_t, behavior, - compat_ulong_t, flags) + compat_int_t, flags) { ssize_t ret; @@ -1327,7 +1308,7 @@ COMPAT_SYSCALL_DEFINE6(process_madvise, ret = compat_import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); if (ret >= 0) { - ret = do_process_madvise(which, upid, &iter, behavior, flags); + ret = do_process_madvise(pidfd, &iter, behavior, flags); kfree(iov); } return ret; _
