git: cf322978d73a - main - mb_unmapped_to_ext(): return error code on error

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=cf322978d73a3ed4958cb64cc4f1b47ceb53a03e

commit cf322978d73a3ed4958cb64cc4f1b47ceb53a03e
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2024-12-28 08:30:01 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2025-01-13 19:29:31 +0000

    mb_unmapped_to_ext(): return error code on error
    
    to allow to distinguish the causes of failure.
    
    Reviewed by:    markj
    Sponsored by:   NVidia networking
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D48265
---
 sys/kern/kern_mbuf.c | 41 +++++++++++++++++++++++++++--------------
 sys/sys/mbuf.h       |  2 +-
 2 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/sys/kern/kern_mbuf.c b/sys/kern/kern_mbuf.c
index 73c98209474a..26be33658ab9 100644
--- a/sys/kern/kern_mbuf.c
+++ b/sys/kern/kern_mbuf.c
@@ -936,8 +936,8 @@ mb_unmapped_free_mext(struct mbuf *m)
 	mb_free_extpg(old_m);
 }
 
-static struct mbuf *
-_mb_unmapped_to_ext(struct mbuf *m)
+static int
+_mb_unmapped_to_ext(struct mbuf *m, struct mbuf **mres)
 {
 	struct mbuf *m_new, *top, *prev, *mref;
 	struct sf_buf *sf;
@@ -947,9 +947,15 @@ _mb_unmapped_to_ext(struct mbuf *m)
 	u_int ref_inc = 0;
 
 	M_ASSERTEXTPG(m);
+
+	if (m->m_epg_tls != NULL) {
+		/* can't convert TLS mbuf */
+		m_freem(m);
+		*mres = NULL;
+		return (EINVAL);
+	}
+
 	len = m->m_len;
-	KASSERT(m->m_epg_tls == NULL, ("%s: can't convert TLS mbuf %p",
-	    __func__, m));
 
 	/* See if this is the mbuf that holds the embedded refcount. */
 	if (m->m_ext.ext_flags & EXT_FLAG_EMBREF) {
@@ -1048,7 +1054,8 @@ _mb_unmapped_to_ext(struct mbuf *m)
 			atomic_add_int(refcnt, ref_inc);
 	}
 	m_free(m);
-	return (top);
+	*mres = top;
+	return (0);
 
 fail:
 	if (ref_inc != 0) {
@@ -1065,13 +1072,15 @@ fail:
 	}
 	m_free(m);
 	m_freem(top);
-	return (NULL);
+	*mres = NULL;
+	return (ENOMEM);
 }
 
-struct mbuf *
-mb_unmapped_to_ext(struct mbuf *top)
+int
+mb_unmapped_to_ext(struct mbuf *top, struct mbuf **mres)
 {
-	struct mbuf *m, *next, *prev = NULL;
+	struct mbuf *m, *m1, *next, *prev = NULL;
+	int error;
 
 	prev = NULL;
 	for (m = top; m != NULL; m = next) {
@@ -1087,12 +1096,15 @@ mb_unmapped_to_ext(struct mbuf *top)
 				 */
 				prev->m_next = NULL;
 			}
-			m = _mb_unmapped_to_ext(m);
-			if (m == NULL) {
-				m_freem(top);
+			error = _mb_unmapped_to_ext(m, &m1);
+			if (error != 0) {
+				if (top != m)
+					m_free(top);
 				m_freem(next);
-				return (NULL);
+				*mres = NULL;
+				return (error);
 			}
+			m = m1;
 			if (prev == NULL) {
 				top = m;
 			} else {
@@ -1111,7 +1123,8 @@ mb_unmapped_to_ext(struct mbuf *top)
 			prev = m;
 		}
 	}
-	return (top);
+	*mres = top;
+	return (0);
 }
 
 /*
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index 434f29feddcf..9373a3c3d656 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -813,7 +813,7 @@ struct mbuf	*mb_alloc_ext_plus_pages(int, int);
 struct mbuf	*mb_mapped_to_unmapped(struct mbuf *, int, int, int,
 		    struct mbuf **);
 int		 mb_unmapped_compress(struct mbuf *m);
-struct mbuf 	*mb_unmapped_to_ext(struct mbuf *m);
+int		 mb_unmapped_to_ext(struct mbuf *m, struct mbuf **mres);
 void		 mb_free_notready(struct mbuf *m, int count);
 void		 m_adj(struct mbuf *, int);
 void		 m_adj_decap(struct mbuf *, int);