Thanks Vijay. I would test them and get back to you.
Regards--
Subrata
On Tue, 2008-08-12 at 23:27 +0530, Vijay Kumar wrote:
> Hi Subrata,
> this patch adds eventfd counter overflow test cases.
>
> Michael, there is a small bug in the eventfd() man page. The man page
> says that in the select() syscall, exceptfds is set when the counter
> overflow occurs. But it is readfds/writefds that is set when the
> counter overflows. POLLERR event in poll() is not equivalent to
> setting of exceptfds. POLLPRI event in poll() is equivalent to setting
> of exceptfds.
>
> Changelog:
>
> * Added eventfd counter overflow test cases.
>
> Signed-off-by: Vijay Kumar <[EMAIL PROTECTED]>
>
> testcases/kernel/syscalls/eventfd/Makefile | 31 ++++++
> testcases/kernel/syscalls/eventfd/eventfd01.c | 130
> ++++++++++++++++++++++++-
> 2 files changed, 160 insertions(+), 1 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/eventfd/Makefile
> b/testcases/kernel/syscalls/eventfd/Makefile
> index e2ebae8..d253431 100644
> --- a/testcases/kernel/syscalls/eventfd/Makefile
> +++ b/testcases/kernel/syscalls/eventfd/Makefile
> @@ -19,10 +19,41 @@
> CFLAGS += -I../../../../include -Wall
> LDLIBS += -L../../../../lib -lltp
>
> +check_header = $(shell \
> + if echo "\#include <$(1)>" | $(CC) -E - > /dev/null 2>&1 ; \
> + then echo yes ; \
> + else echo no ; fi)
> +
> +check_aio_eventfd = $(shell \
> + if echo -e \
> + "\#include <libaio.h>\n\
> + int main() \
> + { \
> + io_set_eventfd(NULL, 0); \
> + return 0; \
> + }" | $(CC) -xc -laio - > /dev/null 2>&1 ; \
> + then echo yes ; \
> + else echo no ; fi)
> +
> +HAS_LIBAIO = $(call check_header,libaio.h)
> +HAS_LIBAIO_EVENTFD = $(call check_aio_eventfd)
> +
> +ifeq ($(HAS_LIBAIO_EVENTFD),yes)
> +CFLAGS += -DHAS_AIO_EVENTFD
> +LDLIBS += -laio
> +endif
> +
> SRCS = $(wildcard *.c)
> TARGETS = $(patsubst %.c, %, $(wildcard *.c))
>
> all: $(TARGETS)
> +ifeq ($(HAS_LIBAIO),no)
> + @echo "Note: Libaio is required for testing eventfd overflow testing.";
> +else
> +ifeq ($(HAS_LIBAIO_EVENTFD),no)
> + @echo "Note: Eventfd support is required in libaio for overflow
> testing.";
> +endif
> +endif
>
> install:
> @set -e; for i in $(TARGETS); do ln -f $$i ../../../bin/$$i ; done
> diff --git a/testcases/kernel/syscalls/eventfd/eventfd01.c
> b/testcases/kernel/syscalls/eventfd/eventfd01.c
> index f099248..ea4f8e1 100644
> --- a/testcases/kernel/syscalls/eventfd/eventfd01.c
> +++ b/testcases/kernel/syscalls/eventfd/eventfd01.c
> @@ -53,16 +53,21 @@
> #include <errno.h>
> #include <string.h>
> #include <stdint.h>
> +#include <poll.h>
>
> #include <test.h>
> #include <usctest.h>
> #include <linux_syscall_numbers.h>
>
> +#ifdef HAS_AIO_EVENTFD
> +#include <libaio.h>
> +#endif
> +
> static void setup(void);
> static void cleanup(void);
>
> char *TCID = "eventfd01";
> -int TST_TOTAL = 12;
> +int TST_TOTAL = 15;
> extern int Tst_count;
>
> static int
> @@ -489,6 +494,128 @@ child_inherit_test(int fd)
> }
> }
>
> +#ifdef HAS_AIO_EVENTFD
> +/*
> + * Test whether counter overflow is detected and handled correctly.
> + *
> + * It is not possible to directly overflow the counter using the
> + * write() syscall. Overflows occur when the counter is incremented
> + * from kernel space, in an irq context, when it is not possible to
> + * block the calling thread of execution.
> + *
> + * The AIO subsystem internally uses eventfd mechanism for
> + * notification of completion of read or write requests. In this test
> + * we trigger a counter overflow, by setting the counter value to the
> + * max possible value initially. When the AIO subsystem notifies
> + * through the eventfd counter, the counter overflows.
> + *
> + * NOTE: If the the counter starts from an initial value of 0, it will
> + * take decades for an overflow to occur. But since we set the initial
> + * value to the max possible counter value, we are able to cause it to
> + * overflow with a single increment.
> + *
> + * When the counter overflows, the following are tested
> + * 1. Check whether POLLERR event occurs in poll() for the eventfd.
> + * 2. Check whether readfd_set/writefd_set is set in select() for the
> + eventfd.
> + * 3. The counter value is UINT64_MAX.
> + */
> +static void
> +counter_overflow_test(int evfd)
> +{
> + io_context_t ctx = 0;
> + int fd;
> + int ret;
> + struct iocb iocb;
> + struct iocb *iocbap[1];
> + static char buf[4 * 1024];
> + uint64_t count;
> +
> + struct timeval timeout = { 10, 0 };
> + fd_set readfds;
> + struct pollfd pollfd;
> +
> + ret = io_setup(16, &ctx);
> + if (ret < 0)
> + tst_resm(TBROK, "io_setup error: %s", strerror(-ret));
> +
> + fd = open("testfile", O_RDWR | O_CREAT, 0644);
> + if (fd == -1) {
> + tst_resm(TBROK, "error creating tmp file: %s",
> + strerror(errno));
> + goto err_io_destroy;
> + }
> +
> + ret = set_counter(evfd, UINT64_MAX - 1);
> + if (ret == -1)
> + goto err_close_file;
> +
> + io_prep_pwrite(&iocb, fd, buf, sizeof(buf), 0);
> + io_set_eventfd(&iocb, evfd);
> +
> + iocbap[0] = &iocb;
> + ret = io_submit(ctx, 1, iocbap);
> + if (ret < 0) {
> + tst_resm(TBROK, "error submitting iocb: %s", strerror(-ret));
> + goto err_close_file;
> + }
> +
> + FD_ZERO(&readfds);
> + FD_SET(evfd, &readfds);
> + ret = select(evfd + 1, &readfds, NULL, NULL, &timeout);
> + if (ret == -1) {
> + tst_resm(TBROK, "error getting evfd status with select: %s",
> + strerror(errno));
> + goto err_close_file;
> + }
> +
> + if (FD_ISSET(evfd, &readfds))
> + tst_resm(TPASS, "read fd set as expected");
> + else
> + tst_resm(TFAIL, "read fd not set");
> +
> + pollfd.fd = evfd;
> + pollfd.events = POLLIN;
> + pollfd.revents = 0;
> + ret = poll(&pollfd, 1, 10000);
> + if (ret == -1) {
> + tst_resm(TBROK, "error getting evfd status with poll: %s",
> + strerror(errno));
> + goto err_close_file;
> + }
> + if (pollfd.revents & POLLERR)
> + tst_resm(TPASS, "POLLERR occurred as expected");
> + else
> + tst_resm(TFAIL, "POLLERR did not occur");
> +
> + ret = read(evfd, &count, sizeof(count));
> + if (ret == -1) {
> + tst_resm(TBROK, "error reading eventfd: %s", strerror(errno));
> + goto err_close_file;
> + }
> +
> + if (count == UINT64_MAX)
> + tst_resm(TPASS, "overflow occurred as expected");
> + else
> + tst_resm(TFAIL, "overflow did not occur");
> +
> + err_close_file:
> + close(fd);
> +
> + err_io_destroy:
> + io_destroy(ctx);
> +}
> +#else
> +static void
> +counter_overflow_test(int evfd)
> +{
> + tst_resm(TCONF, "eventfd support is not available in AIO subsystem");
> + tst_resm(TCONF, "eventfd support is not available in AIO subsystem");
> + tst_resm(TCONF, "eventfd support is not available in AIO subsystem");
> + return;
> +}
> +#endif
> +
> int
> main(int argc, char **argv)
> {
> @@ -536,6 +663,7 @@ main(int argc, char **argv)
> writefd_set_test(fd);
> writefd_not_set_test(fd);
> child_inherit_test(fd);
> + counter_overflow_test(fd);
>
> close(fd);
> }
>
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