[M] Change in libosmocore[master]: Add multiple messages buffers to struct iofd_msghdr

18 Sep 2025

laforge has submitted this change. ( https://gerrit.osmocom.org/c/libosmocore/+/40491?usp=email )
Change subject: Add multiple messages buffers to struct iofd_msghdr
......................................................................
Add multiple messages buffers to struct iofd_msghdr
This is a prerequisite for transfering multiple buffers with a single
SQE or CQE when using osmo_io with io_uring.
The message buffers at struct iofd_msghr, as well as the io vectors are
arrays. A maximum number is stored, as well as the current number.
As this patch does not implement multiple buffers yet, only index 0 of a
message buffer is used. (msg[0])
Having more than one buffer is optional and the number can be controlled
via environment variable.
Related: OS#6705
Change-Id: I4fb1067de4615cc22cc6caf99b481491e7f2ef92
---
M include/osmocom/core/osmo_io.h
M src/core/libosmocore.map
M src/core/osmo_io.c
M src/core/osmo_io_internal.h
M src/core/osmo_io_poll.c
M src/core/osmo_io_uring.c
6 files changed, 74 insertions(+), 16 deletions(-)
Approvals:
  Jenkins Builder: Verified
  pespin: Looks good to me, approved

diff --git a/include/osmocom/core/osmo_io.h b/include/osmocom/core/osmo_io.h
index c8b8517..0b3dc83 100644
--- a/include/osmocom/core/osmo_io.h
+++ b/include/osmocom/core/osmo_io.h
@@ -70,6 +70,14 @@
    OSMO_IO_FD_MODE_RECVMSG_SENDMSG,
 };
+/*! The _operation_ of an osmo_io_fd determines if read or write operation are to be configured used. */
+enum osmo_io_op {
+	/*! change parameters for read() */
+	OSMO_IO_OP_READ,
+	/*! change parameters for write() */
+	OSMO_IO_OP_WRITE,
+};
+
 /*! The back-end used by osmo_io.  There can be multiple different back-ends available on a given system;
  * only one of it is used for all I/O performed via osmo_io in one given process. */
 enum osmo_io_backend {
@@ -204,6 +212,7 @@
 struct osmo_io_fd *osmo_iofd_setup(const void *ctx, int fd, const char *name,
    	  enum osmo_io_fd_mode mode, const struct osmo_io_ops *ioops, void *data);
 int osmo_iofd_set_cmsg_size(struct osmo_io_fd *iofd, size_t cmsg_size);
+int osmo_iofd_set_io_buffers(struct osmo_io_fd *iofd, enum osmo_io_op op, uint8_t buffers);
 int osmo_iofd_register(struct osmo_io_fd *iofd, int fd);
 int osmo_iofd_unregister(struct osmo_io_fd *iofd);
 unsigned int osmo_iofd_txqueue_len(struct osmo_io_fd *iofd);
diff --git a/src/core/libosmocore.map b/src/core/libosmocore.map
index b48c4e6..239597c 100644
--- a/src/core/libosmocore.map
+++ b/src/core/libosmocore.map
@@ -275,6 +275,7 @@
 osmo_iofd_sendmsg_msgb;
 osmo_iofd_set_alloc_info;
 osmo_iofd_set_cmsg_size;
+osmo_iofd_set_io_buffers;
 osmo_iofd_set_data;
 osmo_iofd_set_ioops;
 osmo_iofd_set_priv_nr;
diff --git a/src/core/osmo_io.c b/src/core/osmo_io.c
index 6b4b919..72e30c1 100644
--- a/src/core/osmo_io.c
+++ b/src/core/osmo_io.c
@@ -159,7 +159,8 @@
hdr->action = action;
    hdr->iofd = iofd;
-	hdr->msg = msg;
+	hdr->msg[0] = msg;
+	hdr->io_len = 1;
return hdr;
 }
@@ -407,7 +408,7 @@
  */
 void iofd_handle_send_completion(struct osmo_io_fd *iofd, int rc, struct iofd_msghdr *msghdr)
 {
-	struct msgb *msg = msghdr->msg;
+	struct msgb *msg = msghdr->msg[0];
/* Incomplete write */
    if (rc > 0 && rc < msgb_length(msg)) {
@@ -442,7 +443,7 @@
    	OSMO_ASSERT(0);
    }
-	msgb_free(msghdr->msg);
+	msgb_free(msghdr->msg[0]);
    iofd_msghdr_free(msghdr);
 }
@@ -478,8 +479,8 @@
    	return -ENOMEM;
msghdr->flags = MSG_NOSIGNAL;
-	msghdr->iov[0].iov_base = msgb_data(msghdr->msg);
-	msghdr->iov[0].iov_len = msgb_length(msghdr->msg);
+	msghdr->iov[0].iov_base = msgb_data(msghdr->msg[0]);
+	msghdr->iov[0].iov_len = msgb_length(msghdr->msg[0]);
    msghdr->hdr.msg_iov = &msghdr->iov[0];
    msghdr->hdr.msg_iovlen = 1;
@@ -530,8 +531,8 @@
    	msghdr->hdr.msg_namelen = osmo_sockaddr_size(&msghdr->osa);
    }
    msghdr->flags = sendto_flags;
-	msghdr->iov[0].iov_base = msgb_data(msghdr->msg);
-	msghdr->iov[0].iov_len = msgb_length(msghdr->msg);
+	msghdr->iov[0].iov_base = msgb_data(msghdr->msg[0]);
+	msghdr->iov[0].iov_len = msgb_length(msghdr->msg[0]);
    msghdr->hdr.msg_iov = &msghdr->iov[0];
    msghdr->hdr.msg_iovlen = 1;
@@ -595,8 +596,8 @@
    }
/* build iov from msgb */
-	msghdr->iov[0].iov_base = msgb_data(msghdr->msg);
-	msghdr->iov[0].iov_len = msgb_length(msghdr->msg);
+	msghdr->iov[0].iov_base = msgb_data(msghdr->msg[0]);
+	msghdr->iov[0].iov_len = msgb_length(msghdr->msg[0]);
    msghdr->hdr.msg_iov = &msghdr->iov[0];
    msghdr->hdr.msg_iovlen = 1;
@@ -724,6 +725,9 @@
    iofd->tx_queue.max_length = 1024;
    INIT_LLIST_HEAD(&iofd->tx_queue.msg_queue);
+	iofd->io_read_buffers = 1;
+	iofd->io_write_buffers = 1;
+
    return iofd;
 }
@@ -741,6 +745,41 @@
    return 0;
 }
+/*! Set the number of buffers that can be used in a single read or write operation.
+ *
+ *  If the osmo_io_fd is in OSMO_IO_FD_MODE_READ_WRITE mode, this API function can be used to tell the
+ *  osmo_io proecess how many buffers should be read or written with a single read or write operation.
+ *  This feature is supported with io_uring backend only.
+ *
+ *  \param[in] iofd the iofd file descriptor
+ *  \param[in] op the osmo_io_op (read or write) to set the number of IO buffers for
+ *  \param[in] buffers the number of IO buffer for each specified operation
+ *  \returns zero on success, a negative value on error
+ */
+int osmo_iofd_set_io_buffers(struct osmo_io_fd *iofd, enum osmo_io_op op, uint8_t buffers)
+{
+	if (iofd->mode != OSMO_IO_FD_MODE_READ_WRITE)
+		return -EINVAL;
+
+	if (g_io_backend != OSMO_IO_BACKEND_IO_URING)
+		return -EINVAL;
+
+	if (buffers < 1 || buffers > IOFD_MSGHDR_IO_BUFFERS)
+		return -EINVAL;
+
+	switch (op) {
+	case OSMO_IO_OP_READ:
+		iofd->io_read_buffers = buffers;
+		break;
+	case OSMO_IO_OP_WRITE:
+		iofd->io_write_buffers = buffers;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
 /*! Register the osmo_io_fd for active I/O.
  *
  *  Calling this function will register a previously initialized osmo_io_fd for performing I/O.
@@ -836,7 +875,7 @@
 {
    struct iofd_msghdr *hdr;
    while ((hdr = iofd_txqueue_dequeue(iofd))) {
-		msgb_free(hdr->msg);
+		msgb_free(hdr->msg[0]);
    	iofd_msghdr_free(hdr);
    }
 }
diff --git a/src/core/osmo_io_internal.h b/src/core/osmo_io_internal.h
index 79b3fa9..d28e3d7 100644
--- a/src/core/osmo_io_internal.h
+++ b/src/core/osmo_io_internal.h
@@ -76,6 +76,12 @@
    /*! size of iofd_msghdr.cmsg[] when allocated in recvmsg path */
    size_t cmsg_size;
+	/*! maximum number of message-buffers per read operation */
+	uint8_t io_read_buffers;
+
+	/*! maximum number of message-buffers per write operation */
+	uint8_t io_write_buffers;
+
    struct {
    	/*! talloc context from which to allocate msgb when reading */
    	const void *ctx;
@@ -119,6 +125,7 @@
    IOFD_ACT_SENDMSG,
 };
+#define IOFD_MSGHDR_IO_BUFFERS	8
/*! serialized version of 'struct msghdr' employed by sendmsg/recvmsg */
 struct iofd_msghdr {
@@ -131,12 +138,14 @@
    struct osmo_sockaddr osa;
    /*! io-vector we need to pass as argument to sendmsg/recvmsg; is set up
     * to point into msg below */
-	struct iovec iov[1];
+	struct iovec iov[IOFD_MSGHDR_IO_BUFFERS];
    /*! flags we pass as argument to sendmsg / recvmsg */
    int flags;
+	/*! current number of message-buffers that are stored */
+	uint8_t io_len;
    /*! message-buffer containing data for this I/O operation */
-	struct msgb *msg;
+	struct msgb *msg[IOFD_MSGHDR_IO_BUFFERS];
    /*! I/O file descriptor on which we perform this I/O operation */
    struct osmo_io_fd *iofd;
diff --git a/src/core/osmo_io_poll.c b/src/core/osmo_io_poll.c
index 466973d..d27a5d6 100644
--- a/src/core/osmo_io_poll.c
+++ b/src/core/osmo_io_poll.c
@@ -65,7 +65,7 @@
    		break;
    	case OSMO_IO_FD_MODE_RECVFROM_SENDTO:
    	case OSMO_IO_FD_MODE_RECVMSG_SENDMSG:
-			hdr.msg = msg;
+			hdr.msg[0] = msg;
    		hdr.iov[0].iov_base = msg->tail;
    		hdr.iov[0].iov_len = msgb_tailroom(msg);
    		hdr.hdr = (struct msghdr) {
diff --git a/src/core/osmo_io_uring.c b/src/core/osmo_io_uring.c
index 17853b6..fff632c 100644
--- a/src/core/osmo_io_uring.c
+++ b/src/core/osmo_io_uring.c
@@ -201,7 +201,7 @@
 static void iofd_uring_handle_recv(struct iofd_msghdr *msghdr, int rc)
 {
    struct osmo_io_fd *iofd = msghdr->iofd;
-	struct msgb *msg = msghdr->msg;
+	struct msgb *msg = msghdr->msg[0];
if (rc > 0)
    	msgb_put(msg, rc);
@@ -235,7 +235,7 @@
    	iofd->u.uring.write_msghdr = NULL;
if (OSMO_UNLIKELY(IOFD_FLAG_ISSET(iofd, IOFD_FLAG_CLOSED))) {
-		msgb_free(msghdr->msg);
+		msgb_free(msghdr->msg[0]);
    	iofd_msghdr_free(msghdr);
    } else {
    	iofd_handle_send_completion(iofd, rc, msghdr);
@@ -431,7 +431,7 @@
    	LOGPIO(iofd, LOGL_DEBUG, "Cancelling write\n");
    	iofd->u.uring.write_msghdr = NULL;
    	talloc_steal(OTC_GLOBAL, msghdr);
-		msgb_free(msghdr->msg);
+		msgb_free(msghdr->msg[0]);
    	msghdr->iofd = NULL;
    	io_uring_prep_cancel(sqe, msghdr, 0);
    }
-- 
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Gerrit-MessageType: merged
Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: I4fb1067de4615cc22cc6caf99b481491e7f2ef92
Gerrit-Change-Number: 40491
Gerrit-PatchSet: 13
Gerrit-Owner: jolly andreas@eversberg.eu
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge laforge@osmocom.org
Gerrit-Reviewer: pespin pespin@sysmocom.de



    

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[M] Change in libosmocore[master]: Add multiple messages buffers to struct iofd_msghdr