diff options
Diffstat (limited to 'fs/select.c')
| -rw-r--r-- | fs/select.c | 38 |
1 files changed, 21 insertions, 17 deletions
diff --git a/fs/select.c b/fs/select.c index b3a3a1326af6..a8109baa5e46 100644 --- a/fs/select.c +++ b/fs/select.c @@ -310,11 +310,12 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, s64 *timeout) { fd_set_bits fds; - char *bits; - int ret, size, max_fdset; + void *bits; + int ret, max_fdset; + unsigned int size; struct fdtable *fdt; /* Allocate small arguments on the stack to save memory and be faster */ - char stack_fds[SELECT_STACK_ALLOC]; + long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; ret = -EINVAL; if (n < 0) @@ -333,20 +334,21 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, * since we used fdset we need to allocate memory in units of * long-words. */ - ret = -ENOMEM; size = FDS_BYTES(n); - if (6*size < SELECT_STACK_ALLOC) - bits = stack_fds; - else + bits = stack_fds; + if (size > sizeof(stack_fds) / 6) { + /* Not enough space in on-stack array; must use kmalloc */ + ret = -ENOMEM; bits = kmalloc(6 * size, GFP_KERNEL); - if (!bits) - goto out_nofds; - fds.in = (unsigned long *) bits; - fds.out = (unsigned long *) (bits + size); - fds.ex = (unsigned long *) (bits + 2*size); - fds.res_in = (unsigned long *) (bits + 3*size); - fds.res_out = (unsigned long *) (bits + 4*size); - fds.res_ex = (unsigned long *) (bits + 5*size); + if (!bits) + goto out_nofds; + } + fds.in = bits; + fds.out = bits + size; + fds.ex = bits + 2*size; + fds.res_in = bits + 3*size; + fds.res_out = bits + 4*size; + fds.res_ex = bits + 5*size; if ((ret = get_fd_set(n, inp, fds.in)) || (ret = get_fd_set(n, outp, fds.out)) || @@ -639,8 +641,10 @@ int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout) struct poll_list *walk; struct fdtable *fdt; int max_fdset; - /* Allocate small arguments on the stack to save memory and be faster */ - char stack_pps[POLL_STACK_ALLOC]; + /* Allocate small arguments on the stack to save memory and be + faster - use long to make sure the buffer is aligned properly + on 64 bit archs to avoid unaligned access */ + long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; struct poll_list *stack_pp = NULL; /* Do a sanity check on nfds ... */ |