From: Alex Markuze <amarkuze@redhat.com>
Date: Sun, 16 Mar 2025 19:03:51 +0000 (+0000)
Subject: fixup buffer allocation
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=b756c73bb29c0acb3b2509081debd5dc20045242;p=ceph-client.git

fixup buffer allocation
---

diff --git a/include/linux/ceph/ceph_san_logger.h b/include/linux/ceph/ceph_san_logger.h
index d45c353250e2..7d7846f10839 100644
--- a/include/linux/ceph/ceph_san_logger.h
+++ b/include/linux/ceph/ceph_san_logger.h
@@ -53,4 +53,4 @@ struct ceph_san_tls_ctx *ceph_san_get_tls_ctx(void);
 #define CEPH_SAN_LOG(fmt, ...) \
     ceph_san_log(__FILE__, __LINE__, fmt, ##__VA_ARGS__)
 
-#endif /* CEPH_SAN_LOGGER_H */ 
\ No newline at end of file
+#endif /* CEPH_SAN_LOGGER_H */
\ No newline at end of file
diff --git a/include/linux/ceph/ceph_san_pagefrag.h b/include/linux/ceph/ceph_san_pagefrag.h
index 56907417765c..2475d90fc09f 100644
--- a/include/linux/ceph/ceph_san_pagefrag.h
+++ b/include/linux/ceph/ceph_san_pagefrag.h
@@ -17,8 +17,10 @@ struct cephsan_pagefrag {
 int cephsan_pagefrag_init(struct cephsan_pagefrag *pf);
 int cephsan_pagefrag_init_with_buffer(struct cephsan_pagefrag *pf, void *buffer, size_t size);
 u64 cephsan_pagefrag_alloc(struct cephsan_pagefrag *pf, unsigned int n);
+void *cephsan_pagefrag_get_ptr_from_tail(struct cephsan_pagefrag *pf);
 void cephsan_pagefrag_free(struct cephsan_pagefrag *pf, unsigned int n);
 void cephsan_pagefrag_deinit(struct cephsan_pagefrag *pf);
+void cephsan_pagefrag_reset(struct cephsan_pagefrag *pf);
 void *cephsan_pagefrag_get_ptr(struct cephsan_pagefrag *pf, u64 val);
 
 #define CEPHSAN_PAGEFRAG_GET_N(val)  ((val) >> 32)
diff --git a/net/ceph/ceph_san_logger.c b/net/ceph/ceph_san_logger.c
index 7726a539ce0a..dd120785fcc5 100644
--- a/net/ceph/ceph_san_logger.c
+++ b/net/ceph/ceph_san_logger.c
@@ -95,7 +95,7 @@ struct ceph_san_tls_ctx *ceph_san_get_tls_ctx(void)
         list_add(&ctx->list, &g_logger.contexts);
         spin_unlock(&g_logger.lock);
     }
-
+    cephsan_pagefrag_reset(&ctx->pf);
     /* Set up TLS */
     current->tls.state = ctx;
     current->tls.release = ceph_san_tls_release;
@@ -119,6 +119,7 @@ void ceph_san_log(const char *file, unsigned int line, const char *fmt, ...)
     struct ceph_san_tls_ctx *ctx;
     struct ceph_san_log_entry *entry;
     va_list args;
+    u64 alloc;
     int len;
 
     ctx = ceph_san_get_tls_ctx();
@@ -130,9 +131,12 @@ void ceph_san_log(const char *file, unsigned int line, const char *fmt, ...)
     va_end(args);
 
     /* Allocate entry from pagefrag */ //We need a spinlock here to protect printing
-    u64 alloc = cephsan_pagefrag_alloc(&ctx->pf, sizeof(*entry) + len + 1);
-    if (!alloc)
-        return;
+    alloc = cephsan_pagefrag_alloc(&ctx->pf, sizeof(*entry) + len + 1);
+    while (!alloc) {
+        entry = cephsan_pagefrag_get_ptr_from_tail(&ctx->pf);
+        cephsan_pagefrag_free(&ctx->pf, entry->len);
+        alloc = cephsan_pagefrag_alloc(&ctx->pf, sizeof(*entry) + len + 1);
+    }
     entry = cephsan_pagefrag_get_ptr(&ctx->pf, alloc);
 
     /* Copy to entry buffer */
diff --git a/net/ceph/ceph_san_pagefrag.c b/net/ceph/ceph_san_pagefrag.c
index 7557721a1616..d34918044173 100644
--- a/net/ceph/ceph_san_pagefrag.c
+++ b/net/ceph/ceph_san_pagefrag.c
@@ -54,12 +54,11 @@ u64 cephsan_pagefrag_alloc(struct cephsan_pagefrag *pf, unsigned int n)
 {
     /* Case 1: tail > head */
     if (pf->tail > pf->head) {
-        if (pf->tail - pf->head >= n) {
+        if (pf->tail - pf->head > n) {
             unsigned int prev_head = pf->head;
             pf->head += n;
             return ((u64)n << 32) | prev_head;
         } else {
-            pr_err("Not enough space in pagefrag buffer\n");
             return 0;
         }
     }
@@ -71,12 +70,11 @@ u64 cephsan_pagefrag_alloc(struct cephsan_pagefrag *pf, unsigned int n)
         return ((u64)n << 32) | prev_head;
     } else {
         /* Need to wrap around */
-        if (n <= pf->tail) {
+        if (n < pf->tail) {
             pf->head = n;
             n += CEPHSAN_PAGEFRAG_SIZE - pf->head;
             return ((u64)n << 32) | 0;
         } else {
-            pr_err("Not enough space for wrap-around allocation\n");
             return 0;
         }
     }
@@ -98,6 +96,19 @@ void *cephsan_pagefrag_get_ptr(struct cephsan_pagefrag *pf, u64 val)
 }
 EXPORT_SYMBOL(cephsan_pagefrag_get_ptr);
 
+/**
+ * cephsan_pagefrag_get_ptr_from_tail - Get buffer pointer from pagefrag tail
+ * @pf: pagefrag allocator
+ * @n: number of bytes to get pointer from
+ *
+ * Returns pointer to the buffer region at the tail pointer minus @n bytes.
+ */
+void *cephsan_pagefrag_get_ptr_from_tail(struct cephsan_pagefrag *pf)
+{
+    return pf->buffer + pf->tail;
+}
+EXPORT_SYMBOL(cephsan_pagefrag_get_ptr_from_tail);
+
 /**
  * cephsan_pagefrag_free - Free bytes in the pagefrag allocator.
  * @n: number of bytes to free.
@@ -126,3 +137,15 @@ void cephsan_pagefrag_deinit(struct cephsan_pagefrag *pf)
     pf->head = pf->tail = 0;
 }
 EXPORT_SYMBOL(cephsan_pagefrag_deinit);
+
+/**
+ * cephsan_pagefrag_reset - Reset the pagefrag allocator.
+ *
+ * Resets the head and tail pointers to the beginning of the buffer.
+ */
+void cephsan_pagefrag_reset(struct cephsan_pagefrag *pf)
+{
+    pf->head = 0;
+    pf->tail = 0;
+}
+EXPORT_SYMBOL(cephsan_pagefrag_reset);