The patch titled random: add async notification support to /dev/random has been added to the -mm tree. Its filename is random-add-async-notification-support-to-dev-random.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: random: add async notification support to /dev/random From: Jeff Dike <jdike@xxxxxxxxxxx> Add async notification support to /dev/random. A little test case is below. Without this patch, you get: $ ./async-random Drained the pool Found more randomness With it, you get: $ ./async-random Drained the pool SIGIO Found more randomness #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <errno.h> #include <fcntl.h> static void handler(int sig) { printf("SIGIO\n"); } int main(int argc, char **argv) { int fd, n, err, flags; if(signal(SIGIO, handler) < 0){ perror("setting SIGIO handler"); exit(1); } fd = open("/dev/random", O_RDONLY); if(fd < 0){ perror("open"); exit(1); } flags = fcntl(fd, F_GETFL); if (flags < 0){ perror("getting flags"); exit(1); } flags |= O_NONBLOCK; if (fcntl(fd, F_SETFL, flags) < 0){ perror("setting flags"); exit(1); } while((err = read(fd, &n, sizeof(n))) > 0) ; if(err == 0){ printf("random returned 0\n"); exit(1); } else if(errno != EAGAIN){ perror("read"); exit(1); } flags |= O_ASYNC; if (fcntl(fd, F_SETFL, flags) < 0){ perror("setting flags"); exit(1); } if (fcntl(fd, F_SETOWN, getpid()) < 0) { perror("Setting SIGIO"); exit(1); } printf("Drained the pool\n"); read(fd, &n, sizeof(n)); printf("Found more randomness\n"); return(0); } Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxxxxxx> Signed-off-by: Matt Mackall <mpm@xxxxxxxxxxx> Cc: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/char/random.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff -puN drivers/char/random.c~random-add-async-notification-support-to-dev-random drivers/char/random.c --- a/drivers/char/random.c~random-add-async-notification-support-to-dev-random +++ a/drivers/char/random.c @@ -370,6 +370,7 @@ static struct poolinfo { */ static DECLARE_WAIT_QUEUE_HEAD(random_read_wait); static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); +static struct fasync_struct *fasync; #if 0 static int debug; @@ -533,8 +534,11 @@ static void credit_entropy_bits(struct e r->entropy_count = r->poolinfo->POOLBITS; /* should we wake readers? */ - if (r == &input_pool && r->entropy_count >= random_read_wakeup_thresh) + if (r == &input_pool && + r->entropy_count >= random_read_wakeup_thresh) { wake_up_interruptible(&random_read_wait); + kill_fasync(&fasync, SIGIO, POLL_IN); + } spin_unlock_irqrestore(&r->lock, flags); } @@ -743,8 +747,10 @@ static size_t account(struct entropy_sto else r->entropy_count = reserved; - if (r->entropy_count < random_write_wakeup_thresh) + if (r->entropy_count < random_write_wakeup_thresh) { wake_up_interruptible(&random_write_wait); + kill_fasync(&fasync, SIGIO, POLL_OUT); + } } DEBUG_ENT("debiting %d entropy credits from %s%s\n", @@ -1101,17 +1107,31 @@ static long random_ioctl(struct file *f, } } +static int random_fasync(int fd, struct file *filp, int on) +{ + return fasync_helper(fd, filp, on, &fasync); +} + +static int random_release(struct inode *inode, struct file *filp) +{ + return fasync_helper(-1, filp, 0, &fasync); +} + const struct file_operations random_fops = { .read = random_read, .write = random_write, .poll = random_poll, .unlocked_ioctl = random_ioctl, + .fasync = random_fasync, + .release = random_release, }; const struct file_operations urandom_fops = { .read = urandom_read, .write = random_write, .unlocked_ioctl = random_ioctl, + .fasync = random_fasync, + .release = random_release, }; /*************************************************************** _ Patches currently in -mm which might be from jdike@xxxxxxxxxxx are git-kvm.patch git-x86.patch uml-arch-um-include-inith-needs-a-definition-of-__used.patch uml-implement-get_wchan.patch uml-implement-get_wchan-fix.patch uml-get-rid-of-asmlinkage.patch uml-get-rid-of-asmlinkage-checkpatch-fixes.patch uml-document-new-ubd-flag.patch uml-further-bugsc-tidying.patch uml-further-bugsc-tidying-checkpatch-fixes.patch uml-smp-needs-to-depend-on-broken-for-now.patch uml-console-driver-cleanups.patch uml-clonec-tidying.patch uml-borrow-consth-techniques.patch uml-delete-some-unused-headers.patch uml-allow-lflags-on-command-line.patch uml-tidy-kern_utilh.patch uml-tidy-pgtableh.patch uml-tidy-pgtableh-fix.patch uml-reconst-a-parameter.patch arch-um-remove-duplicate-includes.patch uml-host-tls-diagnostics.patch uml-move-um_virt_to_phys.patch uml-header-untangling.patch uml-header-untangling-fix.patch uml-style-cleanup.patch uml-currenth-cleanup.patch uml-fix-page-table-data-sizes.patch uml-add-virt_to_pte.patch uml-simplify-sigsegv-handling.patch uml-use-ptrace-directly-in-libc-code.patch uml-kill-processes-instead-of-panicing-kernel.patch uml-clean-up-task_size-usage.patch uml-cover-stubs-with-a-vma.patch uml-fix-command-line-cflags-and-ldflags-support.patch uml-style-fixes-in-arch-um-os-linux.patch uml-miscellaneous-code-cleanups.patch uml-style-fixes-in-filec.patch uml-64-bit-tlb-fixes.patch uml-customize-tlbh.patch uml-eliminate-setjmp_wrapper.patch uml-install-panic-notifier-earlier.patch uml-use-barrier-instead-of-mb.patch uml-tidy-helper-code.patch uml-dont-kill-pid-0.patch uml-get-rid-of-syscall-counters.patch uml-dont-allow-processes-to-call-into-stub.patch uml-move-sig_handler_common_skas.patch uml-clean-up-sig_handler_common_skas.patch uml-style-fixes-in-arch-um-kernel.patch uml-signal-handling-tidying.patch uml-remove-init_irq_signals.patch fix-__const_udelay-declaration-and-definition-mismatches.patch create-arch-kconfig.patch add-have_oprofile.patch add-have_kprobes.patch iget-stop-hostfs-from-using-iget-and-read_inode.patch iget-stop-hostfs-from-using-iget-and-read_inode-checkpatch-fixes.patch aout-suppress-aout-library-support-if-config_arch_supports_aout-uml-re-remove-accidentally-restored-code.patch random-add-async-notification-support-to-dev-random.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html