From b7f944411b4a628443f84a542858a8c78847bb48 Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Tue, 29 Sep 2015 18:10:44 -0700 Subject: misc: mic: SCIF poll SCIF poll allows both user and kernel mode clients to wait on events on a SCIF endpoint. These events include availability of space or data in the SCIF ring buffer, availability of connection requests on a listening endpoint and completion of connections when using async connects. Reviewed-by: Nikhil Rao Reviewed-by: Sudeep Dutt Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- include/linux/scif.h | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) (limited to 'include/linux/scif.h') diff --git a/include/linux/scif.h b/include/linux/scif.h index 44f4f3898bbe..b1923ad2ddd3 100644 --- a/include/linux/scif.h +++ b/include/linux/scif.h @@ -93,6 +93,18 @@ enum { typedef struct scif_endpt *scif_epd_t; +/** + * struct scif_pollepd - SCIF endpoint to be monitored via scif_poll + * @epd: SCIF endpoint + * @events: requested events + * @revents: returned events + */ +struct scif_pollepd { + scif_epd_t epd; + short events; + short revents; +}; + #define SCIF_OPEN_FAILED ((scif_epd_t)-1) #define SCIF_REGISTER_FAILED ((off_t)-1) #define SCIF_MMAP_FAILED ((void *)-1) @@ -990,4 +1002,66 @@ int scif_fence_signal(scif_epd_t epd, off_t loff, u64 lval, off_t roff, */ int scif_get_node_ids(u16 *nodes, int len, u16 *self); +/** + * scif_poll() - Wait for some event on an endpoint + * @epds: Array of endpoint descriptors + * @nepds: Length of epds + * @timeout: Upper limit on time for which scif_poll() will block + * + * scif_poll() waits for one of a set of endpoints to become ready to perform + * an I/O operation. + * + * The epds argument specifies the endpoint descriptors to be examined and the + * events of interest for each endpoint descriptor. epds is a pointer to an + * array with one member for each open endpoint descriptor of interest. + * + * The number of items in the epds array is specified in nepds. The epd field + * of scif_pollepd is an endpoint descriptor of an open endpoint. The field + * events is a bitmask specifying the events which the application is + * interested in. The field revents is an output parameter, filled by the + * kernel with the events that actually occurred. The bits returned in revents + * can include any of those specified in events, or one of the values POLLERR, + * POLLHUP, or POLLNVAL. (These three bits are meaningless in the events + * field, and will be set in the revents field whenever the corresponding + * condition is true.) + * + * If none of the events requested (and no error) has occurred for any of the + * endpoint descriptors, then scif_poll() blocks until one of the events occurs. + * + * The timeout argument specifies an upper limit on the time for which + * scif_poll() will block, in milliseconds. Specifying a negative value in + * timeout means an infinite timeout. + * + * The following bits may be set in events and returned in revents. + * POLLIN - Data may be received without blocking. For a connected + * endpoint, this means that scif_recv() may be called without blocking. For a + * listening endpoint, this means that scif_accept() may be called without + * blocking. + * POLLOUT - Data may be sent without blocking. For a connected endpoint, this + * means that scif_send() may be called without blocking. POLLOUT may also be + * used to block waiting for a non-blocking connect to complete. This bit value + * has no meaning for a listening endpoint and is ignored if specified. + * + * The following bits are only returned in revents, and are ignored if set in + * events. + * POLLERR - An error occurred on the endpoint + * POLLHUP - The connection to the peer endpoint was disconnected + * POLLNVAL - The specified endpoint descriptor is invalid. + * + * Return: + * Upon successful completion, scif_poll() returns a non-negative value. A + * positive value indicates the total number of endpoint descriptors that have + * been selected (that is, endpoint descriptors for which the revents member is + * non-zero). A value of 0 indicates that the call timed out and no endpoint + * descriptors have been selected. Otherwise in user mode -1 is returned and + * errno is set to indicate the error; in kernel mode the negative of one of + * the following errors is returned. + * + * Errors: + * EINTR - A signal occurred before any requested event + * EINVAL - The nepds argument is greater than {OPEN_MAX} + * ENOMEM - There was no space to allocate file descriptor tables + */ +int scif_poll(struct scif_pollepd *epds, unsigned int nepds, long timeout); + #endif /* __SCIF_H__ */ -- cgit v1.2.3-59-g8ed1b