Merge tag 'chr-pull-request' of https://gitlab.com/marcandre.lureau/qemu into staging

chardev patch queue

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# gpg: Signature made Mon 02 Dec 2024 12:26:41 GMT
# gpg:                using RSA key 87A9BD933F87C606D276F62DDAE8E10975969CE5
# gpg:                issuer "marcandre.lureau@redhat.com"
# gpg: Good signature from "Marc-André Lureau <marcandre.lureau@redhat.com>" [full]
# gpg:                 aka "Marc-André Lureau <marcandre.lureau@gmail.com>" [full]
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* tag 'chr-pull-request' of https://gitlab.com/marcandre.lureau/qemu:
  chardev/char-mux: make boolean bit check instead of find_next_bit()
  chardev/char-mux: shift unsigned long to avoid 32-bit overflow

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/chardev/char-mux.c b/chardev/char-mux.c
index bda5c45e60..e13042d381 100644
--- a/chardev/char-mux.c
+++ b/chardev/char-mux.c
@@ -316,6 +316,8 @@ bool mux_chr_attach_frontend(MuxChardev *d, CharBackend *b,
 {
     unsigned int bit;
 
+    QEMU_BUILD_BUG_ON(MAX_MUX > (sizeof(d->mux_bitset) * BITS_PER_BYTE));
+
     bit = find_next_zero_bit(&d->mux_bitset, MAX_MUX, 0);
     if (bit >= MAX_MUX) {
         error_setg(errp,
@@ -325,7 +327,7 @@ bool mux_chr_attach_frontend(MuxChardev *d, CharBackend *b,
         return false;
     }
 
-    d->mux_bitset |= (1 << bit);
+    d->mux_bitset |= (1ul << bit);
     d->backends[bit] = b;
     *tag = bit;
 
@@ -334,15 +336,12 @@ bool mux_chr_attach_frontend(MuxChardev *d, CharBackend *b,
 
 bool mux_chr_detach_frontend(MuxChardev *d, unsigned int tag)
 {
-    unsigned int bit;
-
-    bit = find_next_bit(&d->mux_bitset, MAX_MUX, tag);
-    if (bit != tag) {
+    if (!(d->mux_bitset & (1ul << tag))) {
         return false;
     }
 
-    d->mux_bitset &= ~(1 << bit);
-    d->backends[bit] = NULL;
+    d->mux_bitset &= ~(1ul << tag);
+    d->backends[tag] = NULL;
 
     return true;
 }
@@ -351,7 +350,7 @@ void mux_set_focus(Chardev *chr, unsigned int focus)
 {
     MuxChardev *d = MUX_CHARDEV(chr);
 
-    assert(find_next_bit(&d->mux_bitset, MAX_MUX, focus) == focus);
+    assert(d->mux_bitset & (1ul << focus));
 
     if (d->focus != -1) {
         mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_OUT);