| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <send-serie.davidel@xmailserver.org.13805.1173910770.13>
Date: Wed, 14 Mar 2007 15:19:21 -0700
From: Davide Libenzi <davidel@...ilserver.org>
To: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Ingo Molnar <mingo@...e.hu>,
Suparna Bhattacharya <suparna@...ibm.com>,
Zach Brown <zach.brown@...cle.com>,
Benjamin LaHaise <bcrl@...ck.org>
Subject: [patch 13/13] signalfd/timerfd/asyncfd v5 - KAIO asyncfd support (example/maybe-broken) ...
This is just an example about how to add asyncfd support to the current
KAIO code.
Patch is small and comments says it all about my doubts.
I made a quick test program to verify the patch, and it runs fine here:
http://www.xmailserver.org/asyncfd-aio-test.c
The test program uses poll(2), but it'd, of course, work with epoll too.
This can allow to schedule both block I/O and other poll-able devices
requests, and wait for results using select/poll/epoll.
Signed-off-by: Davide Libenzi <davidel@...ilserver.org>
- Davide
Index: linux-2.6.20.ep2/fs/aio.c
===================================================================
--- linux-2.6.20.ep2.orig/fs/aio.c 2007-03-14 09:41:42.000000000 -0700
+++ linux-2.6.20.ep2/fs/aio.c 2007-03-14 10:31:53.000000000 -0700
@@ -30,6 +30,7 @@
#include <linux/highmem.h>
#include <linux/workqueue.h>
#include <linux/security.h>
+#include <linux/asyncfd.h>
#include <asm/kmap_types.h>
#include <asm/uaccess.h>
@@ -422,6 +423,7 @@
req->private = NULL;
req->ki_iovec = NULL;
INIT_LIST_HEAD(&req->ki_run_list);
+ req->ki_asyncfd = ERR_PTR(-EINVAL);
/* Check if the completion queue has enough free space to
* accept an event from this io.
@@ -463,6 +465,8 @@
{
assert_spin_locked(&ctx->ctx_lock);
+ if (!IS_ERR(req->ki_asyncfd))
+ fput(req->ki_asyncfd);
if (req->ki_dtor)
req->ki_dtor(req);
if (req->ki_iovec != &req->ki_inline_vec)
@@ -947,6 +951,30 @@
return 1;
}
+ /*
+ * Check if the user asked us to deliver the result through an
+ * asyncfd. Note that asyncfd_add_results() may sleep. It seems
+ * OK looking at the code, but I'm not sure since inside a USB driver,
+ * aio_complete() is called with a spinlock held. !!CHECK
+ */
+ if (unlikely(!IS_ERR(iocb->ki_asyncfd))) {
+ struct asyncfd_result asr;
+
+ asr.cookie = iocb->ki_user_data;
+ asr.obj = (unsigned long) iocb->ki_obj.user;
+ asr.res = res;
+ asr.res2 = res2;
+ if ((ret = asyncfd_add_results(iocb->ki_asyncfd, &asr, 1)) != 1) {
+ /*
+ * Here I dunno what to do in case the userspace result
+ * ring is full, or if -EFAULT is returned. !!CHECK
+ */
+
+ }
+ spin_lock_irqsave(&ctx->ctx_lock, flags);
+ goto put_rq;
+ }
+
info = &ctx->ring_info;
/* add a completion event to the ring buffer.
@@ -1556,6 +1584,18 @@
fput(file);
return -EAGAIN;
}
+ if (iocb->aio_resfd != 0) {
+ /*
+ * If the aio_resfd field of the iocb is not zero, get an
+ * instance of the file* now. This will be the place to deliver
+ * AIO results to.
+ */
+ req->ki_asyncfd = asyncfd_fget((int) iocb->aio_resfd);
+ if (IS_ERR(req->ki_asyncfd)) {
+ ret = PTR_ERR(req->ki_asyncfd);
+ goto out_put_req;
+ }
+ }
req->ki_filp = file;
ret = put_user(req->ki_key, &user_iocb->aio_key);
Index: linux-2.6.20.ep2/include/linux/aio.h
===================================================================
--- linux-2.6.20.ep2.orig/include/linux/aio.h 2007-03-14 09:42:16.000000000 -0700
+++ linux-2.6.20.ep2/include/linux/aio.h 2007-03-14 10:17:24.000000000 -0700
@@ -119,6 +119,12 @@
struct list_head ki_list; /* the aio core uses this
* for cancellation */
+
+ /*
+ * If the aio_resfd field of the userspace iocb is not zero,
+ * this is the underlying file* to deliver event to.
+ */
+ struct file *ki_asyncfd;
};
#define is_sync_kiocb(iocb) ((iocb)->ki_key == KIOCB_SYNC_KEY)
Index: linux-2.6.20.ep2/include/linux/aio_abi.h
===================================================================
--- linux-2.6.20.ep2.orig/include/linux/aio_abi.h 2007-03-14 09:42:51.000000000 -0700
+++ linux-2.6.20.ep2/include/linux/aio_abi.h 2007-03-14 09:46:11.000000000 -0700
@@ -84,7 +84,11 @@
/* extra parameters */
__u64 aio_reserved2; /* TODO: use this for a (struct sigevent *) */
- __u64 aio_reserved3;
+ __u32 aio_reserved3;
+ /*
+ * If different from 0, this is an asyncfd to deliver AIO results to
+ */
+ __u32 aio_resfd;
}; /* 64 bytes */
#undef IFBIG
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists