git: 1a71d24ecd0d - main - kern/sys_process.c: make vmspace_rwmem() similar to io functions

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=1a71d24ecd0dbaf61fd2a44166e9be07c328b198

commit 1a71d24ecd0dbaf61fd2a44166e9be07c328b198
Author:     Konstantin Belousov <[email protected]>
AuthorDate: 2026-08-14 05:46:07 +0000
Commit:     Konstantin Belousov <[email protected]>
CommitDate: 2026-08-14 14:35:38 +0000

    kern/sys_process.c: make vmspace_rwmem() similar to io functions
    
    In particular, if there were any bytes moved, and then vm_fault()
    faulted, do not return an error, but report the short io instead.
    
    PR:     297512
    Reviewed by:    markj
    Tested by:      Stéphane D'Alu <[email protected]>
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D58838
---
 sys/kern/sys_process.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index 73e6b64e900b..46848ca150c0 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -451,6 +451,7 @@ vmspace_rwmem(struct vmspace *vm, struct uio *uio)
 	vm_map_t map;
 	vm_offset_t pageno;		/* page number */
 	vm_prot_t reqprot;
+	ssize_t orig_resid;
 	int error, fault_flags, page_offset, writing;
 
 	map = &vm->vm_map;
@@ -464,10 +465,12 @@ vmspace_rwmem(struct vmspace *vm, struct uio *uio)
 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
 
+	orig_resid = uio->uio_resid;
+
 	if (writing) {
 		error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
 		if (error != 0)
-			goto out;
+			return (error);
 	}
 
 	/*
@@ -524,9 +527,7 @@ vmspace_rwmem(struct vmspace *vm, struct uio *uio)
 		vm_page_unwire(m, PQ_ACTIVE);
 
 	} while (error == 0 && uio->uio_resid > 0);
-
-out:
-	return (error);
+	return (uio->uio_resid == orig_resid ? error : 0);
 }
 
 int