Re: [RFC PATCH 2/6] ram_blocks: Convert to a QLIST

Chris Wright
2010-06-08T21:27:03Z

* Alex Williamson (alex.williamson@redhat.com) wrote:
> extern int phys_ram_fd;
> -extern uint8_t *phys_ram_dirty;
> extern ram_addr_t ram_size;
> -extern ram_addr_t last_ram_offset;
> +
> +typedef struct RAMBlock {
> + uint8_t *host;
> + ram_addr_t offset;
> + ram_addr_t length;
> + QLIST_ENTRY(RAMBlock) next;
> +} RAMBlock;
> +
> +typedef struct RAMList {
> + uint8_t *phys_dirty;
> + ram_addr_t last_offset;
> + QLIST_HEAD(ram, RAMBlock) blocks;
> +} RAMList;
> +extern RAMList ram;

such a generic name for global namespace

> void *qemu_get_ram_ptr(ram_addr_t addr)
> {
> - RAMBlock *prev;
> - RAMBlock **prevp;
> RAMBlock *block;
>
> - prev = NULL;
> - prevp = &ram_blocks;
> - block = ram_blocks;
> - while (block && (block->offset > addr
> - || block->offset + block->length <= addr)) {
> - if (prev)
> - prevp = &prev->next;
> - prev = block;
> - block = block->next;
> - }
> - if (!block) {
> - fprintf(stderr, "Bad ram offset %" PRIx64 "\n", (uint64_t)addr);
> - abort();
> - }
> - /* Move this entry to to start of the list. */
> - if (prev) {
> - prev->next = block->next;
> - block->next = *prevp;
> - *prevp = block;
> + QLIST_FOREACH(block, &ram.blocks, next) {
> + if (addr - block->offset < block->length) {
> + QLIST_REMOVE(block, next);
> + QLIST_INSERT_HEAD(&ram.blocks, block, next);
> + return block->host + (addr - block->offset);
> + }
> }
> - return block->host + (addr - block->offset);
> +
> + return NULL;

Why not preserve the error message and abort()? In error cases this
would now just segfault.

Minor nits aside, this too looks like a nice cleanup.

Acked-by: Chris Wright <chrisw@redhat.com>