[Cryptodev-linux-devel] [PATCH 7/8] implement the poll() file operation

[Phil Sutter]

Since there is an asynchronous operation mode, poll() is useful to find
out whether data can be written out or read in.
---
 cryptodev_main.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/cryptodev_main.c b/cryptodev_main.c
index 09d2c41..5c35e92 100644
--- a/cryptodev_main.c
+++ b/cryptodev_main.c
@@ -39,6 +39,7 @@
 #include <linux/random.h>
 #include <linux/syscalls.h>
 #include <linux/pagemap.h>
+#include <linux/poll.h>
 #include <linux/uaccess.h>
 #include "cryptodev.h"
 #include <linux/scatterlist.h>
@@ -92,6 +93,7 @@ struct crypt_priv {
        struct locked_list free, todo, done;
        int itemcount;
        struct work_struct cryptask;
+       wait_queue_head_t user_waiter;
 };
 
 #define FILL_SG(sg, ptr, len)                                  \
@@ -765,6 +767,9 @@ static void cryptask_routine(struct work_struct *work)
        mutex_lock(&pcr->done.lock);
        list_splice_tail(&tmp, &pcr->done.list);
        mutex_unlock(&pcr->done.lock);
+
+       /* wake for POLLIN */
+       wake_up_interruptible(&pcr->user_waiter);
 }
 
 /* ====== /dev/crypto ====== */
@@ -791,6 +796,7 @@ cryptodev_open(struct inode *inode, struct file *filp)
        mutex_init(&pcr->free.lock);
        mutex_init(&pcr->todo.lock);
        mutex_init(&pcr->done.lock);
+       init_waitqueue_head(&pcr->user_waiter);
 
        for (i = 0; i < DEF_COP_RINGSIZE; i++) {
                tmp = kzalloc(sizeof(struct todo_list_item), GFP_KERNEL);
@@ -932,6 +938,9 @@ static int crypto_async_fetch(struct crypt_priv *pcr,
        list_add_tail(&item->__hook, &pcr->free.list);
        mutex_unlock(&pcr->free.lock);
 
+       /* wake for POLLOUT */
+       wake_up_interruptible(&pcr->user_waiter);
+
        return retval;
 }
 
@@ -1211,6 +1220,21 @@ cryptodev_compat_ioctl(struct file *file, unsigned int 
cmd, unsigned long arg_)
 
 #endif /* CONFIG_COMPAT */
 
+static unsigned int cryptodev_poll(struct file *file, poll_table *wait)
+{
+       struct crypt_priv *pcr = file->private_data;
+       int ret = 0;
+
+       poll_wait(file, &pcr->user_waiter, wait);
+
+       if (!list_empty_careful(&pcr->done.list))
+               ret |= POLLIN | POLLRDNORM;
+       if (!list_empty_careful(&pcr->free.list) || pcr->itemcount < 
MAX_COP_RINGSIZE)
+               ret |= POLLOUT | POLLWRNORM;
+
+       return ret;
+}
+
 static const struct file_operations cryptodev_fops = {
        .owner = THIS_MODULE,
        .open = cryptodev_open,
@@ -1219,6 +1243,7 @@ static const struct file_operations cryptodev_fops = {
 #ifdef CONFIG_COMPAT
        .compat_ioctl = cryptodev_compat_ioctl,
 #endif /* CONFIG_COMPAT */
+       .poll = cryptodev_poll,
 };
 
 static struct miscdevice cryptodev = {
-- 
1.7.2.2



_______________________________________________
Cryptodev-linux-devel mailing list
Cryptodev-linux-devel@gna.org
https://mail.gna.org/listinfo/cryptodev-linux-devel